The Ultra inserts are Trim-Tec's best inserts yet! The Ultra XDS is a 3mm insert that will fit all our current wheels. Harder than our performance inserts, the Ultra can last (depending on conditions) up to 150 head of cattle trimmed before having to index. The Ultra inserts are meant to be used on Free stall, sandy and gritty feet only. The Ultra inserts' longevity and toughness will help you save time and even more money while trimming. The Ultra XDS is the more aggressive choice of insert compared to the Ultra XDC (see on inserts/blades page) The Ultra insert is the hardest grade insert that Trim-Tec offers.