This Butler Creek flip-open scope cover, it is size 11, which fit a 1.55" or 39.4mm. To measure your scope, use calipers and measure straight across your scope, from side to side passing through middle of the scope. Please keep in mind that the cover goes completely around the end of the scope, it does not cover just the glass.
These are from a Leupold contract with Butler creek, therefore these are all marked Leupold, not Butler Creek.
We are not responsible for mis-measurements on your part.