Prime Line 7-07498 Ball Joint Replacement for Model MTD 723-0448A, 923-0448A Fits 1997-Up RT99LT & GT 400, 600, 800 Series Thread Size: RT 3/8 x 24NF; Thread Length 5/8" Internal Threads: RT 7/16 x 20NF; Internal Thread Depth: 7/8" Barrel Length: 1 11/64"