OEM Part #61-0850-003.00" OD x 13.63" O/A Large (retracted)Includes: Cylinder, 1/4-20 x 1-3/4” lg. stainless steel socket head cap screw and Threadlocker 242 (RPI Part #RPA032)Uses Hydraulic fluid (RPI Part #RPF449)Fits: Between Baseplate and Upper Structure of ChairModel(s) This Part Fits: Priority 1005Check Serial Numbers HereFits Serial Numbers M2-0196 to present ONLY.Will NOT fit Serial Numbers M1-0001 through M2-0195.