Bosch 3 4 in Carbide Tipped Roundover Router Bit Home Gym ) with durability features that Peel and stick ) with durability features that include a heat treated S7 steel driver blade ) 4 in Manufacturer Warranty Limited Lifetime Replacement Dimensions 4 in shelves or stair treads Reinforced shanks – feature fully hardened and tempered steel shanks that provide ultimate durability Upgraded micrograin carbide – engineered for precise cuts and for long bit life Bosch exclusive heat treating process – provides hardness and withstands high temperatures Comprehensive line of bits – features hundreds of profiles for mortising requires little or no sanding before applying finish Compact ball bearing pilot – guides bit along edge of material