A twin-action rear shock absorber for the Yamaha XT 660Z/Tenere 08-16. YSS introduces the new 506 RTL rear suspension through the Z Series range. This is a new high-performance suspension unit, nitrogen - oil, with adjustment of the spring preload and the rebound damping. This particular range is fully rebuildable. Suspension Type: With a Single Nitrogen Oil Chamber Rebuildable: Yes Suspension Category Rear Mono Shock Suspension Type With a Single Nitrogen Oil Chamber Piston Diameter 45 mm Shaft Diameter 16 mm Suspension Length 345 mm Spring Preload Threaded Rebound Adjustment Yes Length Adjustment No Compression Adjustment No