10PCS Water Bottle Cage Bolts Holder Screws, Bike Bicycle Cycling Bracket Rack Bolts Screws Accessories, Stainless Steel M5x12mm Hex Socket Head Screw

These are good quality hardware. I had no problem with them threading into my bike mounts and they function perfectly with a 4mm hex key

Works perfectly for a pair of electric bikes that needed bottles mounted.

These are sized and threaded for bicycle down tubes and seat tubes, for attaching water bottle holders and other assorted accessories that are slim enough to not interfere with pedaling. I personally attach a water bottle holder to the seat tube and my bike lock on the down tube.Of course, they are tightened with a allen wrench, but with the ribbing on the head, you can hand tighten them upon insertion until it's time to use the allen wrench. These are supposed to be stainless steel. In time, if they rust, I'll update this review; however, all indications is that they will stand up to the elements just fine.

Well machined, accurately sized, good quality parts.