1. Your website lacks explanation of the nominal sizes you give to the various pressure cooker sealing rings. When placing an on-line order, the potential customer needs to know whether you are referring to inside or outside dia.of the ring. 2. Having ordered the wrong ring for my cooker, due to the omission above, I made a 20mile trip to Berry Hill Road (the return address) to exchange it, only to be told that this was the incorrect place. 3. On telephoning 'Customer Service' to try to resolve the matter, I was held in a queue for 7 minutes+. At this point I gave up and went home - another 20 mile journey! Thanks Tower.