Made out of steel dom tubing, has two inches of adjustment. Available in 18"-20", 19"-21", 20-22", 21"-23", and 22"-24" Body #1 with a WM40A and is 18''-20''. Body #1 with the WM40AM and is 19''-21'' Body #2 with the WM40A and is 20''-22'' Body #2 with the WM40AM and is 21''-23'' Body #2 with the WM40AL and is 22''-24''