It's all in the design. All Grub® are 100% waterproof keeping feet warm, dry, and protected in harsh weather and messy working conditions. The secret – our exclusive self-insulating waterproof CR-foam shell construction. The CR-foam bootie material acts as a "neutral medium" between inside and outside temperatures. Naturally lightweight, buoyant, and very comfortable, the material keeps the foot and lower leg warm and protected in cold and wet conditions.
Natural rubber overlays act as a protective skin for the upper bootie. The upper has a triple reinforced toe area and a quadruple reinforced heel area. The outsole is made of high abrasion natural rubber. The rubber in the boots will stay flexible for years.

Standard U.S sizes for men and women (unisex sizing). Boots and shoes are available in whole sizes only, but will stretch to fit half sizes. There is a 15mm toe allowance built into the sizing. Our boots and shoes are made to standard widths, but the materials will stretch comfortably to fit widths up to a EEEE. For narrow feet, we suggest wearing a thicker sock or putting in an additional sockliner to take up room.

No. The upper calf and topline areas are made of soft, flexible CR-foam and will "stretch-fit" to virtually any calf girth. With the flexible upper, the pant leg can be worn over or inside the boot. The collar material can be turned down to allow hands-free removal and vent humidity in warmer working conditions.

It isn't necessary unless activities are planned for extreme cold conditions. The CR-foam bootie material is rated sub-zero during active use and will effectively withstand freezing temperatures for up to one hour. Medium-weight athletic socks should provide the best fit. The upper will stretch to accommodate thicker socks.

Thinsulate®, made by 3M® Corporation, is typically used in work boots and hiking shoes to resist cold temperatures. Thinsulate® is typically laminated to the whole shoe lining or glued into the toe area of a shoe or boot. It is not a waterproof material. Gore-Tex® is a breathable, waterproof membrane but is not an insulating material. The CR-foam used in Grub's® is both waterproof and self-insulating. Our materials exceed the long-term effectiveness of waterproof membrane materials and provide greater insulating properties than all non-specialty temperature-control substrates.