This aircraft-quality aluminum tubing is ideal for making your tie rod, trailing arms, or other suspension components. The 5/8" tap tubing has a 1.00" O.D. with a .562 I.D. ready to be tapped to 5/8-18. The 3/4" tap tubing has a 1 1/8" O.D. with a .687 I.D. ready to be tapped to 3/4-16.