LA Spas Replacement Bag Filters fit the black LA Spas Filter Bag Basket They are for all model years if you currently use the Filter Bag Basket with the 3-inch male threaded ends. Question. What are the differences in the LA Spa Replacement Bag Filter and the LA SPA FILTER BAG OEM FD-51500 Answer: The replacement filters are made by a manufacturer who makes 65 percent of all filters out there. The OEM filters are made by MAAX Spas who owns the brand LA Spa. The replacement filters are double glazed versus the OEM are triple glazed. What glazed means. A glaze is an element used for the filtration. The more glaze the stronger it filters the water. The replacement filters tend to run slightly larger than the OEM initially but do shrink a little. But the most important factor is the use of the proper rubber o-ring and the proper use of it. The o-ring purchased from us is tight and its meant to be. The filter O-ring should be placed at the very bottom of the filter basket. Cleaning Your Filters: Filters should be cleaned every 3-4 weeks depending on the spa usage. Have 2 sets of filters. One clean set and one set in use. Use a filter cleaner for best results After cleaning the filters, DO NOT LET THEM DRY WITHOUT RINSING rinse each filter thoroughly with light pressure hot water. Hang to dry.