Comparison : Item # 816P, 3 Inch (in) Aluminum Pneumatic Vapor Valve for 16 Inch (in) Man Hole Covers
Item # 820P, 3 Inch (in) Aluminum Pneumatic Vapor Valve for 20 Inch (in) Man Hole Covers
Item # 816P-RK, Repair Kit for 3 Inch (in) Aluminum Pneumatic Vapor Valve for 16 Inch (in) Man Hole Covers
Item # 820P-RK, Repair Kit for 3 Inch (in) Aluminum Pneumatic Vapor Valve for 20 Inch (in) Man Hole Covers