The Unicel 4CH-35 hot tub filter with a handle on the top and 1-½ inch MPT threaded bottom is a compatible replacement for the Hot Springs 31382 filter and the Sundance Spas 6540-486 filter. Occasionally hot tub manufacturers may vary the filter size for the same hot tub model. Therefore it’s best to confirm that this filter is the same size as the filter in your Hot Springs or Sundance spa model before ordering to ensure proper fitment.
