Alan, After review of the site you reference, the Parker Hannifin O-ring web site appears to be a much more thorough site. It’s catalog is a great source for an education on O-rings and the sizing of grooves to support the O-rings. In addition there is a web-based program for picking the proper O-ring for your application and the sizing of its associated groove. It also has links for European designs. You have to look a bit to find this info and I am not sure if this link will work: http://www.parker.com/portal/site/PARKER/menuitem.734d2913eb3c11da13576f849420d1ca/?vgnextoid=d195f87357e28110VgnVCM10000048021dacRCRD&vgnextfmt=default&division=b126981ef31a0110VgnVCM10000048021dacRCRD&literaturetype=Catalogs&searchAttr=searchResult&languages=EN&parentCh=Division#results R/Jay Resepectfully, Jay K. Jeffries Andros Is., Bahamas Save the whales, collect the whole set. From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alan James Hi Glen, Didn't the Aussies play well. Below is a link to a good article on seals. Alan |