Effective immediately, Softub Canada is discontinuing the Small Collar filter. This is due to installation issues on the 3.5” suction cover. Many customers have had issues installing and uninstalling the filters causing the suction covers to break. We have conversion kits available to convert the 3.5” suction covers to our standard 5” suction covers. This will require use of our standard filter part#4619. The conversation kit contains our 5 inch Filter and the threaded collar that is threaded into the original suction fitting. This collar holds the new suction cover attachment. This can be installed while water is still in the tub.