Introducing our Skull Pattern Shifter Shaft Extensions, available in 6, 9, 12, and 18-inch lengths. With a sleek skull pattern finish, these extensions are designed to fit Peterbilt Shifter Shaft (UP21740). Featuring a thread-on design with a 1/2 inch 1 13 Unified National Coarse (UNC) thread, these extensions are easy to install. The thread is 1 inch long, and the diameter of the shaft is 3/4 inches. Practical and stylish, our Skull Pattern Shifter Shaft Extensions are sold individually, offering a convenient solution for enhancing your shifter shaft.