The mounting system requiring the disposer to be held in place while the locking collar is twisted was very difficult. I tried numerous time both by myself and with an assistant but could not get the locking collar started. I finally used a jack to hold the disposer in place while turning the locking collar. Then trying to turn the collar far enough to fully lock the disposer in place was very difficult, even with the suggested petroleum jelly. There was no good way to get enough leverage on the ring because the small tabs only stick out about an inch. Next time I'll buy another brand.