Gill Waterproof Boot Sock in Graphite | 2021 The new Gill Waterproof Boot Sock has been designed for wearing under boots when enjoying water sporting adventures. Made long enough to wear with boots and both waterproof and breathable, these Boot Socks are ideal for occasions when you expect to tackle low to medium levels of water. The thermal inner provides extra warmth, while the Nylon outer layer ensures durability. These socks have been designed with 80% Nylon on the outer, 20% Elastane on the inner and 50% Merino, 50% Acrylic. Features   Durable Nylon outer layer. Thermal inner sock with wicking capability. Longer length for use in boots. Waterproof and breathable Sizing   Small - UK3.5 - UK5  Medium - UK5.5 - UK8 Large - UK9 - UK13