You are Buying a White 4" Spa Diverter Handle Knob only. This Diverter Knob mounts on top of the Diverter Valve Stem Square that is about 7/16" Wide sticking through the diverter cap. The Diverter Valve that this part fits is used to Divert Water into different sides of a hot tub and fits many different brands. The outside measurement of the Handle is about 4" from end to end and is about 2" wide from side to side. The Square hole where the stem mounts is about 7/16" wide. The list on this handle is $14.99. This Part is used in Many Brands of Hot Tubs With Gray Colored Parts . We have plenty of these. This listing is for the Handle only all other parts shown are for illustration only and sold separately. We offer the Cap and Handle in different colors and shapes and the o-rings, Stem and Complete valves & Kits in our Store.