Review on 🔩 High-Quality Zinc Plated Carbon Steel Rivet Nut Flat Head Insert Nutsert Pack of 50 (5/16-18) - Durable and Reliable Solution for Secure Fastening by Chris Bhatia

Probably M6 inserts. When I tried to screw one of these onto the mandrel of the setting tool, it didn't make a full turn and wouldn't unscrew any further. Tried another, same result. When the third failed to tie, I began to suspect they were the wrong size. 1/4"-20 is almost 6mm (6.4mm) and the thread pitch is a bit coarser so I tried a 1/4"-20 screw. He went inside. In an incorrectly marked package, as in the photo, it is clearly visible that the package is marked "M6". I'm glad I didn't need them right away and decided to check first. In the photos, the D-ring screw is 1/4"-20, the threaded black shank is an M6 tool mandrel. Note that the 1/4"-20 screw is fully threaded into the socket. I put a screw in the bottom of the liner because the screw is short. UPDATE: I notified the seller and they quickly rectified the situation. They support their product, bugs occur and they fix the problem. Thanks very much!