This is a replacement seal for nearly all Volvo Penta crankshaft mounted raw water pumps / sea water pumps. The garter spring is stainless steel. This is a single lip seal to allow debris not to get stuck near the shaft causing shaft damage.  It has a helix lip which is also adds extra protection against leaks. Seal is located directly behind the impeller. If you have any fitment questions just ask. The Volvo Penta equivalent part number is 827247 .  Remember to change your seal at the first sight of your pump dripping.  If it leaks into your bearings you will need to rebuild your pump.  Check out my other listings for rebuild kits.   Thanks.