My 2001 outside cab Silverado shocks were definitely broken and needed new ones. I thought I should try them as they have good reviews and the price is quite affordable. With old and new. Two 13mm bolts are attached to the lower arm and two 13mm nuts to the upper part. I reused the two 13mm bolts and tightened the one 14mm nut that came with the new shocks. The whole process took about 1 hour for both sides. The ride with these new shock absorbers is much better than with the old blown ones. They are not stiff at all, which worries me, and tolerate bumps very well. My overall satisfaction, I rate this product 5 stars. After more than 5 months with these shocks and more time, my rating has definitely changed! Now they feel a little better than shock absorbers when riding around town, but in deeper dives or on highways these shock absorbers are useless. Do not buy them if you are looking to upgrade or replace worn shock absorbers. Spend a little more and buy name brand shock absorbers instead of wasting money on it and buying a better replacement as a result.