Grubs RAINLINE use a lightweight, easy-clean, rubber shell in a classic field boot style. The full stretch panel in the shaft gives great calf fit, is neoprene and completely waterproof. The RAINLINE features a removable 6mm Nitrocell footbed that adds further insulation and cushioning due to its microscopic closed cell nitrogen bubble structure, giving the wearer superior thermal protection from cold surfaces. The excellent new Trax (Duraprene rubber) outsole gives superior grip on a variety of surfaces and features Hexors technology.