Product_description: ['One door closer body for all applications Adjustable spring power allows 351 closers a size range of 1 through 6. They are adjusted to size 3 before leaving the factory High impact non-corrosive plastic covers standard, metal optional. Both secured with two machine screws Captivated brass valves Standard pressure relief valves for both opening and closing cycles protect the door & frame from damage caused by abuse Heavy Duty Construction Heat treated full closed rack and pinion provide control from the full open position Heavy duty one piece die cast aluminum silicon alloy body with 14% silicon provides superior strength and wear resistance 1/2" arm engagement over a 7/16 square spindle ensures a wear-resistant tight joint Machine screws and self tapping screws provided for closer and arm In addition, wood screws supplied when installed on wood doors without through bolts Interchangeable forged steel arms Parallel arm Forged Steel Constructions Permits 120 opening at standard mounting Permits 180 opening at alternate mounting Can be used with the 351L retrofit plate when replacing a LCN 4040 closer Heavy duty forged steel arms are finely finished and interchangeable between SARGENT 351, 1431 and 281 series Brass body low sensitivity control valves offer separate regulating for door speed, latching, backcheck and optional delayed action All valves are controlled by an 1/8" Allen wrench to discourage tampering and are captivated to prevent removing valves from the body and damaging door closer Adjustable backcheck (standard) protects the door and hardware from damage during the opening cycle Adjustable delayed action permits easy access for physically impaired individuals Valves are captivated to prevent accidental removal Finish: EN Sprayed Aluminum Enamel (BHMA 689)'] (Page 1)