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Base layers

MOBIUSPHY Alkey

A fleece-lined windproof thermal underwear set in a fabric stated to stretch four ways, published for motorcycling among winter activities, in European sizing.

MOBIUSPHY fleece-lined thermal underwear set

MOBIUSPHY Alkey

A fleece-lined windproof thermal underwear set in a fabric stated to stretch four ways, published for motorcycling among winter activities, in European sizing.

Lining
High-quality fleece, stated windproof for cold weather (maker’s bullet)
Stretch
Four-way stretch fabric, stated for full freedom of movement (maker’s bullet)
Sizing
European standard sizing, stated not to shrink (maker’s bullet)
Stated use
Motorcycling, skiing, cycling, winter walking (maker’s bullet)
Moisture
Moisture-regulating fibre, stated to move sweat away and keep the wearer dry and warm (maker’s bullet)
Composition
The maker puts nothing in writing on this.
Amazon reference
B07WK2MC6B (one reference across 5 Amazon marketplaces)
EAN
0761426818951
  • Fleece lining published as the insulation, not implied
  • Motorcycling named first among its stated uses
  • No fibre composition published at all

Best for: Cold-weather riding where warmth matters more than bulk.

≈ £15 / €20
Check price on Amazon

Specifications

Lining
High-quality fleece, stated windproof for cold weather (maker’s bullet)
Stretch
Four-way stretch fabric, stated for full freedom of movement (maker’s bullet)
Sizing
European standard sizing, stated not to shrink (maker’s bullet)
Stated use
Motorcycling, skiing, cycling, winter walking (maker’s bullet)
Moisture
Moisture-regulating fibre, stated to move sweat away and keep the wearer dry and warm (maker’s bullet)
Composition
The maker puts nothing in writing on this.
Amazon reference
B07WK2MC6B (one reference across 5 Amazon marketplaces)
EAN
0761426818951

What the seller commits to paper

A high-quality fleece lining, stated windproof. A four-way stretch fabric for freedom of movement. European standard sizing, stated not to shrink. Moisture-regulating fibre. Uses named as motorcycling, skiing, cycling and winter walking.

Sizing stated is a real feature

Thermal sets on this shelf are often cut to a different market’s sizing and listed without mention. A maker that states European sizing has answered the question that generates most of the returns in this category.

Fleece is a decision, not a detail

A fleece lining is warmth and it is bulk. Under a riding jacket with its own thermal liner, that can be one layer too many — and on a January commute it is exactly right. Knowing it is fleece rather than “thermal” is what lets that be judged.

The rows this seller leaves empty

The fibre composition. Nothing at all: no percentages, no fibre names. Three other sets in this family publish theirs, and one of them publishes a fabric weight as well.

Availability

Between 20 € and 26 € across the German, French, Italian and Spanish Amazon stores, in the single reading behind this page.

Priced in local currency, which the euro range above deliberately leaves out, it also appears on the British Amazon store.

Nothing whatever came back from the American Amazon store, so the buy button there opens a search instead of an empty page.

What Keepa returned in the single reading behind this page. Availability and prices move without notice.

Prices quoted in this text were read on 18 September 2026. The live price is at the top of the page.

More base layers

  • ALPIDEX thermal underwear set in black and red

    ALPIDEX 15100

    A two-piece thermal set in 70% polyamide, 25% polyester and 5% elastane with extra-flat seams and placed ventilation panels, cut to sit unnoticed under ordinary clothes.

    Composition
    70% polyamide / 25% polyester / 5% elastane (maker’s bullet)
    Seams
    Extra-flat, for comfort and freedom of movement under jeans and a pullover (maker’s bullet)
    Ventilation
    Deliberately placed panels for air circulation and heat regulation (maker’s bullet)
    Durability
    The polyamide content is stated to stop the fabric stretching out after repeated washing (maker’s bullet)
    Set contents
    Trousers and long-sleeved top; sizes S/M, L/XL, 2XL/3XL (maker’s bullet)
    Fabric weight
    The maker puts nothing in writing on this.
    Amazon reference
    B07V3N2JPL (one reference across 6 Amazon marketplaces)
    EAN
    4251379348309
    • Full three-fibre composition published to the percentage
    • Explains what the polyamide is there for, rather than just listing it
    • No fabric weight and no temperature range published

    Best for: Layering under ordinary clothes and riding kit alike, where seams and bulk are the complaint.

    ≈ €14
    Check price on Amazon
  • Alpinestars Ride Tech V2 base layer bottoms in black and red

    Alpinestars Ride Tech V2 Bottom Summer

    A motorcycle base layer in polypropylene with elastane, published by its maker as not melting under abrasion — the only listing in this family to address that property.

    Composition
    Polypropylene with elastane fabric (maker’s bullet)
    Abrasion behaviour
    The maker states the fabric does not melt under abrasion (maker’s bullet)
    Construction
    Double layers, stated for additional moisture handling (maker’s bullet)
    Function
    Part of a range for regulating internal temperature (maker’s bullet)
    Stated use
    Motorcycling first, then skiing, hiking and other outdoor activity (maker’s bullet)
    Fabric weight
    The maker puts nothing in writing on this.
    Amazon reference
    B08WNC73GD (one reference across 6 Amazon marketplaces)
    EAN
    8059175286704
    • The only base layer here that publishes how its fabric behaves under abrasion
    • A motorcycle equipment maker publishing a motorcycle property
    • The most expensive base layer here, by roughly three times

    Best for: Wearing under leathers or a suit, where what the layer next to your skin is made of has been thought about.

    ≈ $90 / £65 / €66
    Check price on Amazon
  • FlowFlex seamless thermal underwear set in black

    FlowFlex Thermal set

    A seamless thermal set in 94% nylon and 6% elastane at 200 g/m², published for a temperature range of −15 °C to 10 °C, stretching to 220% and drying in twenty minutes.

    Composition
    94% nylon / 6% elastane (maker’s bullet)
    Fabric weight
    200 g/m² (maker’s bullet)
    Temperature range
    −15 °C to 10 °C (maker’s bullet)
    Stretch
    Four-way, to 220% without deformation (maker’s bullet)
    Drying
    Stated to dry in 20 minutes (maker’s bullet)
    Cut
    European proportions — sleeves +2 cm, legs +1.5 cm; machine washable at 40 °C (maker’s bullet)
    Amazon reference
    B0FC2GSZJN (one reference across 5 Amazon marketplaces)
    EAN
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    • Publishes five separate figures where its neighbours publish adjectives — weight, temperature range, stretch, drying time and cut adjustment
    • A fabric weight AND a temperature range together, which is the pair that decides the season
    • Nothing published about abrasion behaviour — see the Alpinestars listing in this family

    Best for: Winter riding where you want to know before buying which temperatures the layer was built for.

    ≈ €21
    Check price on Amazon

The rest of this rider’s shelf

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    ATE SL DOT 4, 5 L

    A five-litre DOT 4 brake fluid whose bullets consist of the product name twice, a quality claim and a claim of ergonomic design — with no standard or boiling point published.

    DOT grade
    DOT 4 (from the title)
    Volume
    5 litres — 5000 ml (from the title)
    Standards
    NOT published in the bullets — no FMVSS, no ISO 4925 class, no SAE reference.
    Boiling points
    The maker puts nothing in writing on this.
    Listing bullets
    Four: "ATE brake fluid SL 5 ltr", "ergonomic design", "high quality", "ATE brake fluid SL 5 ltr".
    Miscibility
    The maker puts nothing in writing on this.
    Amazon reference
    B003VXPY4K (one reference across 6 Amazon marketplaces)
    EAN
    4006633490030
    • From a brake manufacturer that publishes its own technical data
    • A five-litre container for a workshop or several machines
    • No standard, no ISO class and no boiling point published anywhere in the listing

    Best for: A rider who already uses this fluid and is re-ordering it by name.

    ≈ €32
    Check price on Amazon
  • Bosch DOT 4 brake fluid 500 ml bottle

    Bosch DOT 4, 500 ml

    A 500 ml DOT 4 brake fluid published to three standards with a dry boiling point of at least 230 °C and a stated two-year replacement interval.

    Dry boiling point
    ≥ 230 °C (maker’s bullet) — the only boiling point published in this family
    Standards
    FMVSS § 571.116 DOT 4, SAE J 1704, ISO 4925 Class 4 (maker’s bullet)
    Replacement interval
    Every 2 years, with the vehicle manufacturer’s own requirement taking precedence (maker’s bullet)
    Volume
    500 ml (from the title)
    ABS
    Inhibitor components stated to act as a protective lubricant against noise, wear and corrosion (maker’s bullet)
    Stated compatibility
    Suitable for vehicles manufactured before 2010 (maker’s bullet)
    Amazon reference
    B00P3XXJFC (one reference across 6 Amazon marketplaces)
    EAN
    4047025114592
    • Publishes a dry boiling point in degrees — the only fluid in this family to do so
    • Publishes a change interval AND defers to the vehicle manufacturer on it
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    Best for: One brake bleed on a machine specified for DOT 4, opened and finished the same day.

    ≈ £13 / €11
    Check price on Amazon
  • Liqui Moly DOT 4 brake fluid 500 ml bottle

    Liqui Moly DOT 4, 500 ml

    A 500 ml DOT 4 brake fluid published to three standards with a viscosity figure of 1800 mm²/s, stated miscible with high-quality synthetic brake fluids.

    Viscosity
    1800 mm²/s (from the title)
    Specifications
    FMVSS 116 DOT 3 / 116 DOT 4 | ISO 4925 Class 3 / Class 4 | SAE J 1703 / J 1704 (maker’s bullet)
    Volume
    500 ml (from the title)
    Miscibility
    Miscible and compatible with high-quality synthetic brake fluids (maker’s bullet)
    Low temperature
    Stated excellent low-temperature behaviour (maker’s bullet)
    Boiling points
    Stated extremely high wet and dry — no figure is given (maker’s bullet)
    Amazon reference
    B07L4T6LPF (one reference across 6 Amazon marketplaces)
    EAN
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    • Publishes a viscosity figure, which no other fluid in this family does
    • Three standards including the ISO class
    • Boiling points described rather than given, where one rival publishes ≥ 230 °C

    Best for: One brake bleed, on a machine that sees cold mornings.

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All base layers