10 Pack Black Steel Tubular Rivets 5/16" (L), Quality rivets for a professional result, Ideal for dog collars, leashes, halters, bridles, belts and so much more, Head diameter is 5/16", tube diameter is 1/8", post length is 5/16", Rivet post should be about 1/8" longer than the material being riveted to ensure a proper finish, Hill Leather Company