Our sprinkler system is over 40 years old and consists of spray heads and brass impact heads both single and double stream. The sprinklers fit into these quick couplers which are in the ground and have either alumminum or blue plastic covers. You lift the lid, then screw the brass key which holds the 1" sprinklers. Trouble is that the rubber inside of them is old and cracked, and they leak everywhere, reducing pressure and making the areas around them soggy. What are these things called, our local suppliers haven't heard of them and can't figure out what I am talking about. I have Nelson model 30 and rain bird, neither fits the other. Also the system is mostly galvanized pipe, so you know what fun that is to repair. They are rebuildable, the Nelsons but contacting the company hasn't seemed to help. I would like to get the flat seals for the valve and the round seals for the key to valve. Does anyone have experience with this system? Any advice is appreciated, but I am not going to update to gear driven heads as it would involve nasty plumbing headaches, and it's kind of relaxing to see the streams of water and hear the tap tap sound. Last resort is to get some rubber tubing and flat rubber stock I guess!