SK Hand Tools 3896 1/2" Drive Palm Control Reversible Ratchet. Features & Benefits: Accessibility Plus Strength. The 72 tooth ratchet head design delivers superior accessibility through its compact head and 5º effective swing arc. 17 teeth are engaged during use, with each tooth bearing only 6% of the drive load-providing strength and durability. Quick and Efficient. Thumbwheel reversing mechanism enables easy change of direction while free-wheeling back plate allows application of steadying pressure without reversing.