Wheel adapter studs 9/16"-18 thread size with 2.6" overall length (L1). Knurl diameter (D1) is 0.56". Compatible with some of our 8 lug wheel adapters that come in 9/16" thread size studs (except for 8650-8650D in 1.5" and 2" thickness). They are not compatible with our 2-piece conversion adapter studs.