Our 1 3/8” fittings have an inner diameter of 1 3/8”. Which works with 1 3/8” EMT pipe or chain link fence top rail that has an outer diameter of 1 5/16”.
Our 1 5/8” fittings have an inner diameter of 1 3/4”. Which works with 1 5/8” chain link fence top rail/fence post that has an outer diameter of 1 11/16”.