Kleinn Air Horns 320 All-Metal Push Button Terminator Offers a Rugged All Metal Push Button Switch Includes One Perfectly Discreet and Nearly Bulletproof Trigger Features an Easy to Hide Visible Button Measuring A Mere 3/4-Inches In Diameter Designed with an Ultra-flush Mount Requiring a Miniscule 2-Millimeter Minimum Mounting Thickness Designed with a 55/64 Button Flange