EasyPro Stratus SRC rocking piston compressors contain these wearable internal components. Like tires on your car, these parts need to be replaced over time. Repair kit model SRC50K includes piston cup, cylinder, O-rings and cup retainer screws for Stratus SRC series (Gen 2) compressor. (Please Note: Leaf valves are no longer included in the kit. A complete leaf valve plate is available because screws holding leaf valves are susceptible to breaking, which makes individual leaf valve replacement very difficult. SRC50VP - sold separately - is a complete valve plate with leaf valves installed should they be needed.)