Dead Ringer DropBox-Parent Patented Universal Front And Rear Sight System Designed To Fit 1/4", 5/16" And 3/8" Vent Ribbed Shotguns Rear Sight Shooting System Designed For Waterfowl, Wing And Predator Hunting Easy Installation With Universal Mounting System Drop Box Can Be Used As A Gauge To Determine Distance Durable Optical Lexan Light Pipe Construction Includes Interchangeable Light Pipes With Patented Twist Lock Keyway System Built In Leads For Easy Target Acquisition Optimal In Low Light Conditions