We replace boots with 100% Neoprene boots that we import from a factory in China that is under our ownership (80%) and another factory that we have been working with for about 6 years (20%). We have been importing U-Joints from the same place for around 10 years. Boots are not just a general boot for all applications but are specific to match the application being used. There are several boots where it's the same boot across several numbers, I believe we have 1200 SKUs of Axles and around 500 Parts of boots. (I don't have exact numbers available).
When we find a factory that produces quality parts we stay with them. In offering a lifetime warranty on a part with a small margin, we have to be confident that we won't need to go through the cost to warranty the part.
As we've been expanding, we have continued to improve our quality by investing in the right tools to have a good finished product. Our return/warranty on Axles is around 1 per 700, (higher if you include people who purchased the wrong part).