The most durable boot in Simms' impressive line-up The G4 Powerlock Boot is renowned for its durability and grip. Upper features Lorenz synthetic leather with abrasion-resistant synthetic mesh and overlays in high-abrasion areas for added durability. Dual-density midsole provides a balance of comfort and support and a molded TPU heel cup provides ankle stability on steep slopes and slippery rocks. In addition to the felt outsole, these boots feature Simms' new integrated Powerlock cleat system which allows you to easily switch between TPU and aluminum cleats for extra traction on slippery rocks and uneven river bottoms. Pair with Simms G4 Stockingfoot waders for a premium package that your fishing friends will envy.