The Butler Creek Element Scope Caps are highly rugged with a multi-flex sleeve. The objective flip out printable dope disk provides wind and elevation information. Create a watertight, airtight seal lens cover you can open with a touch of a button so you can put your shot through the narrow window of opportunity in the most extreme conditions. 1.73-1.97" (45-50mm) Model ESC50 180 & 270 degree lip open positions Interchangeable disk inserts for changing environments Stainless steel hardware Strong polymer material to withstand punishment Multi-fit design with 10 total caps in line to fit 95% of scopes on the market