Butler Creek 11 Objective Flip Open Scope Cover Fast, flip open design, custom fit for most scopes Water-tight, custom-fit friction mounts anchors them to your scope, air-tight semi-O-ring keeps out dust and moisture Truly ambidextrous, silent spring hinges won't spook game Instant action lids pop open at the touch of a thumb Performs from- 40 to 120 Degrees F, weighs less than an ounce Fast, flip open design, custom fit for most scopes Water-tight, custom-fit friction mounts anchors them to your scope, air-tight semi-O-ring keeps out dust and moisture Truly ambidextrous, silent spring hinges won't spook game Instant action lids pop open at the touch of a thumb Performs from- 40 to 120 Degrees F, weighs less than an ounce Please watch related video for instruction on sizing