5/16-18 Roll-In T-Nut with Ball Spring 48 PACK Our Roll-in T-nuts with ball spring provide a fastening option that can be installed from the profile end or side, Perfect for applications where the ends are inaccessible. The ball spring holds the T-nut in the T-slot, even when the profile is in a vertical position, simplifying the assembly process. Compatible with 80/20 13040 & 15 Series or 40 Series profiles with 8mm slot. Bright Zinc finish, 5/16-18 thread. Pack of 48 individual T-Nuts