This replacement filter cartridge matches the technical specifications as Unicel # C-4618, Pleatco # PC18-4, Filbur # FC-3740 and OEM # PC-18. This filter cartridge with its 18 inch length and 4 ¾ inch width provides clean and clear water for your pool and spas and suits the most to Coleco F-225,F-235,F-345,DR-18, Lomart 60-4314. It has 1 ¼ inch open hole at its top while 2 7/16 inch open hole at the bottom. Very easy to install this filter cartridge is made of high quality of materials.