VIBRAM is an Italian based sole manufacturer renowned for their high grip mountaineering soles. The company was form shortly after the end of the Second World War in the foothills of the Alps of Northern Italy by its founder and keen climber Vittorio Bramani. GRUBS was the first company to put a VIBRAM sole on a Rubber boot in 2006 and has continued to work closely to bring innovative new products to market. SPEYLINE 4.0 a traditional boot designed with comfort and stability at the forefront. Classic bellows -gives great calf fit. 3MM INSUFOAM-ULTRA (tm) NEOPRENE LINING - Gives the wearer added comfort and warmth. 6mm NITROCELL footbed - provides a soft cushioning for an athletic shoe feel. TheNITROCELL footbed has a million microscopic nitrogen bubbles that insulate the wearer from cold surfaces no need for special Welly Socks that roll down and rub. VIBRAM BRISTOLsole- featuresENCAPSULATED FOAM technology in the heel absorbs heel strike shock for day long comfort. SUPERDRIlining - wicks moister away from the wearers foot to prevent a sweaty and uncomfortable feel it is fungus and rot proof so will not smell like cotton lined boots. COMFORT RATING - -20c to +20c. We recommend purchasing the same UK size as your regular daily footwear such as a trainer. Grubs Boots have a 15mm allowance for a wool blend / thicker sock which also means if you are a half size we recommend sizing down.