Most GRUBS® Rubber footwear uses our self-insulating INSU-FOAM ULTRA™bootie construction which acts as a neutral medium between the wearer and the outside. The bootie is both waterproof and insulating and exceeds the long-term effectiveness of waterproof membranes and lofted insulations. Our boots are waterproof to EN ISO 20344: 2004 5.7 standard.
We use a super stretch Chloroprene material commonly used in Deep sea dry suits, this material has a 300% stretch and is covered with a 4 way stretch knitted nylon jersey which as suggested can expand not only in width but also height. This super stretch means the bootie can stretch up to 150% as a laminate with our SUPER-DRI™, moisture wicking terry knit lining. INSU-FOAM ULTRA™has a fine micro cellular structure, which stops heat transfer through its structure. The microscopic bubbles of air are so small that it is waterproof even in 3.5mm thickness.
INSU-FOAM ULTRA™is super soft and super bouncy, it has a compression set of less than 7% verses 20-25% for other neoprene boots, they remain soft and comfortable for much longer than our competitors. Other manufacturers use Styrene Butadiene Rubber, SBR, foams that are stiffer and harden over time, SBR also has a larger and more irregular bubble structure, boots made of this material are harder, making them uncomfortable and prone to leak through the bootie.
PLEASE NOTE, these are on their way in to us and should arrive 18th may .