3/16" MEDIUM 1/2" HEAD MULTI GRIP RIVET This Multi-Grip Rivet is a real time saver for many repair jobs and only requires one person. Unlike standard pop rivets, these 'blind' rivets do not require a backup washer. 1.) Works in over-sized, oblong and worn out holes up to 1/4″ 2.) Tight clamp-up and holding power, from .257″ to .598″ with stronger clamping power. 3.) NO back-up washer needed. The Multi-Grip action will clamp without needing a back up washer. 4.) These rivets will work with any functioning blind rivet setting tool. These Multi-Grip rivets are often used in applications where the holes have either become oval or just too big for standard 3/16″ diameter rivets.