Look at step 1 on page 18 of the manual, and it shows a nylon washer that goes over the shock shaft (internally).

If you use the recommended shock mounting positions (inside lower hole on rear, outer lower hole on front) then you want 1 limiter on all 4 shocks. Page 23 & 24 tells you to add/remove limiters if you change these lower mounting positions.

http://www.teamassociated.com/pdf/ca...021%202012.pdf