Jus added a kx91 I'm a maintence freak, jus to tell y'all teeth are cheap and should be replaced after they are worn my newest machine I bought used and the teeth were wore to the shank 4 hours later I have two off. Instead of the 20 min it ussually takes, also in the 10 years I've been digging around utlities tiger teeth are your worst enemy. Digging spades will do most anything if they don't work u probably need a bigger tractor, or more patiance....