The Master Spa's Twilight-Legend-Therapool Hot Tub Filter This serves as the Original Equipment Master Spas Filter Cartridge. It fits all Master Spas Twilight Series and Michael Phelps Legend Series Spas from 2017 to the present, with the exception of the triangle-shaped TS 240. It is also compatible with the Therapool SE and Therapool D swim spas from 2017 to the present. When considering purchasing filters, thoroughly review the dimensions provided in the listing. Any recommendations we offer are merely suggestions and should not be considered guarantees. Upon receiving your filters, refrain from removing the protective hygienic wrapper until you are confident they are the correct fit for your spa. The hygienic wrapper must remain completely intact for us to process a refund should the filter not fit. Castle Hot Tubs suggests cleaning your filters once a week using a product such as AquaFinesse Filter Cleaning Tablets. However, if your spa is not in continual use, washing them every other week is also sufficient. Additionally, we advise keeping a spare set of filters for alternate usage. Castle Hot Tubs has established itself as a trusted name in the water care industry. We strive to ensure that your purchasing experience with us is pleasant. If, for any reason, you are not 100% happy with our service, we will address it promptly. Please contact us directly before leaving negative feedback! Thank you! Regarding postage: We dispatch goods promptly upon receiving payment. Orders placed before 1 pm are shipped out the same day. Our couriers handle deliveries from Monday to Friday. Any items ordered on weekends or bank holidays are dispatched on the following working day. For deliveries to the Scottish Highlands & Islands, Isle of Man, Scilly Isles, Channel Islands, Northern Ireland, or destinations outside the UK mainland, please reach out to us for a postal quote before finalizing your purchase. Thank you.