Hey guys I’m a hammer tech at Gorilla hammers in Randolph Massachusetts, the hammer in the picture looks like a old Kent 40 G. If you roll the hammer on it’s back, with the hoses facing up, there will be an adjuster on the right hand side, a nut with an allen in the center. There will be a serial number ingraved below it. The G series is Kent’s first line of hydraulic hammers. An old one but a good one. Kent is also know as FRD or Furukawa Rock Drill. Give our shop a call with any questions about hammers or hammer parts at 1781 986 3905. Thanks and have a good day.