Steel setscrews with 1/4-20 thread and nylon-tipped for fixing the Fixture Block to the rail. Use as replacements or spares or for any other use where a non-marring setscrew is required.

The nylon pad protects the surface the setscrew is locking against. In a Fixture Block, the setscrews can be replaced by nylon-tipped Thumbscrews for toolless operation. These setscrews can also be used with BT3K T-Nuts to make stop blocks in the rail slots.

No, the picture does not show actual size. If it did, we would not lose so many when they fall on the floor.