Just screw the assembly on the dillon factory adjustment bolt. The Dillon factory screw requires a wrench when adjusting the amount of powder to dispense in your powder thrower. Armanov Clickable Dillon Precision Powder Thrower Adjustment Knob easily allows the user to hand adjust the powder dispenser without the need for tools. Unlike other competitors, Arman's button is laser cut with 50 graduations. It's giving the user reference points when adjusting. Two steel spring loaded balls generates smooth and repetable clicks. Easy to setup between multiple loads or even calibres, very precise 50 clicks per turn. Testing on pistol powders one click increments about 0.015 grains. This is very precise setting. Works on Dillon 1050, 650, 750, 550, SDB and 900 presses. This accessory is a must for every Dillon owner help speed up powder adjustment amounts and quick change between multiple loads or even multiple calibers. No disassembly or even original bolt movement required. You keep current powder setting. From aircraft grade aluminum - anodized black color. 1 x laser etched knob assembly 1 x allen wrench NO POWDER BAR OR POWDER THROWER INCLUDED