Clive.. There is a tank on Ebay that shows rather well the "lips" to hold the film in a tank the 2840 and also holds the film away from the walls.....has these same lips, but smaller..... Remember this tank will NOT fit a CPE2.... it is an expert series 3000 tank..... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1390995448&rd=1 Frank Filippone red735i@earthlink.net