This is for where the Aqualock unit fits onto the standard dishwasher tap. Mine leaks. It's bigger and thicker than a normal 3/4" dishwasher tap washer, and has a profile rather than being just flat. Its external diameter is about 25mm and internal 16mm (hard to be accurate as its distorted) whereas an ordinary washer is 23.5 mm ext, 12mm int. See pic, with Aqualock washer on the right. I've tried a standard washer but it just leaks. I've googled all the usual suspects - espares etc - but no luck, and my half-Yorkshire, half-Scottish heritage is too strong to let me shell out £70 for a full new hose - which in any case seems to be a discontinued part. Any suggestions welcome.