FROSTLINE 5.0
FROSTLINE 5.0 is insulated and waterproof, with excellent grip, designed for all-day comfort.
Key Features
- 5MM INSU-FOAM ULTRA Provides all-round foot comfort and insulation.
- 6mm NITROCELL footbed Offers soft cushioning and contains microscopic nitrogen bubbles for insulation from cold surfaces.
- UNDERFOOT CHASSIS Delivers a stable, sure-footed platform.
- HEXZORB technology Absorbs heel strike shock for long-lasting comfort.
- SUPERDRI lining Hard-wearing, moisture-wicking, and resistant to fungus and rot for odor-free performance.
- TRAX outsole Offers superior grip on various surfaces, designed to move with your foot.
- Comfort Rating: -20ºC to +20ºC
INSU-FOAM ULTRA Technology
Most GRUBS® Rubber footwear uses our self-insulating INSU-FOAM ULTRA bootie, acting as a neutral barrier between your foot and the environment. It is both waterproof and insulating, surpassing traditional waterproof membranes. Our boots are tested to EN ISO 20344:2004 5.7 standards.
The bootie uses a super-stretch Chloroprene material (like that used in deep sea dry suits) which stretches up to 300%. It's laminated with a 4-way stretch nylon jersey, allowing expansion in width and height. When combined with SUPERDRI terry knit lining, the laminate stretches up to 150% while keeping moisture away.
INSU-FOAM ULTRA features a fine micro-cellular structure that prevents heat transfer. Even at 3.5mm thickness, it remains fully waterproof. With a compression set of less than 7% (vs. 2025% for typical neoprene), it stays soft and comfortable for longer. Competing materials like SBR are stiffer, degrade faster, and are more likely to leak.
5.0 TECHNOLOGY
The bootie is lined with SUPERDRI terry knit that offers 100% stretch to fit most calves. As INSU-FOAM ULTRA is temperature neutral, it keeps your feet comfortable from 85ºF to sub-zero conditions for extended wear.
TRAX Sole
The TRAX sole uses DURAPRENE rubber and integrates HEXZORB technology to absorb shock and enhance grip. The tread is engineered with zones for grip, traction, stability, and braking, moving with the action of your foot.
Sizing Guide
| UK Size | Boot Height (mm) | Calve Width (mm) |
|---|---|---|
| UK 3 | 370mm | 400mm |
| UK 4 | 370mm | 400mm |
| UK 5 | 375mm | 410mm |
| UK 6 | 380mm | 410mm |
| UK 7 | 385mm | 420mm |
| UK 8 | 390mm | 420mm |
| UK 9 | 395mm | 430mm |
| UK 10 | 400mm | 430mm |
| UK 11 | 405mm | 440mm |
| UK 12 | 410mm | 440mm |
| UK 13 | 415mm | 450mm |
Note: Our Wellington Boots include a 15mm allowance for wool blend/combination socks.
We recommend purchasing your regular comfortable footwear size. For half sizes, consider sizing down due to this allowance.