{"title":"21ft Swim Spas Parts \u0026 Accessories","description":"\u003cp\u003eReplacement filters and parts for 21ft Master Spas swim spas including the H2X Trainer 21, H2X Challenger 21, and MP Momentum series. Use our year selector above to make sure you get the right filter for your model year.\u003c\/p\u003e","products":[{"product_id":"master-spas-two-r4-2-fpt-four-ma40-filter-set","title":"MasterSpas Two R4 (2\" FPT) \u0026 Four MA40 (2\" FPT) Filter Set","description":"\u003cp\u003e\u003c!--StartFragment --\u003e\u003c\/p\u003e\n\u003cp\u003eThis filter set is the \u003cstrong\u003eexact replacement\u003c\/strong\u003e required for the \u003cem\u003e2025 MasterSpas Challenger 21 D\u003c\/em\u003e and \u003cem\u003eTrainer 21 D\u003c\/em\u003e swim spas. Each R4 cartridge, built with a \u003cstrong\u003e2‑inch female pipe thread connector\u003c\/strong\u003e, is designed to house the EcoPur® Charge Mineral Cartridge inside. The four MA40 cartridges install alongside the R4s to complete the filtration system, delivering the full water clarity and purification balance your swim spa was engineered for.\u003c\/p\u003e\n\u003cp\u003eIncludes:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e2 × Master Clear MA‑R4 Filters (2\" FPT)\u003c\/strong\u003e – Primary cartridges designed to capture dirt, debris, and particles.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e2 × EcoPur® Charge Mineral Cartridges\u003c\/strong\u003e – Fit inside the R4s for mineral purification.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e4 × Master Clear MA‑40 Filters\u003c\/strong\u003e \u003cstrong\u003e(2\" FPT)\u003c\/strong\u003e – Cartridges that work with the R4s to deliver full system performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eImportant Fit Notes:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e✅ Fits \u003cstrong\u003e2025+ Challenger 21 D\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e✅ Fits \u003cstrong\u003e2025+ Trainer 21 D\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e❌ Not compatible with other Trainer or Challenger models outside these specifications\u003c\/li\u003e\n\u003cli\u003e❌ Not compatible with older swim spas using the \u003cstrong\u003eR4 (1.5\" MPT) bundles\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e🗓️ \u003cstrong\u003eReplacement Schedule\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFilters: Replace every \u003cstrong\u003e12 months\u003c\/strong\u003e with regular care, or every \u003cstrong\u003e6 months\u003c\/strong\u003e with heavier use\u003c\/li\u003e\n\u003cli\u003eEcoPur® cartridges (inside the R4s): Replace every \u003cstrong\u003e6 months\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003ePlease verify your swim spa’s model and production year before purchase. Due to the nature of the product, we cannot accept returns on opened or incorrectly ordered filter sets.\u003c\/p\u003e\n\u003cp\u003e\u003c!--EndFragment --\u003e\u003c\/p\u003e","brand":"Master Spas West","offers":[{"title":"Default Title","offer_id":45344535183497,"sku":null,"price":519.98,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0752\/6491\/7641\/files\/IMG_2351.webp?v=1772582795"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0752\/6491\/7641\/collections\/model-trainer21-deep_62f364f4-851b-4686-b33d-eccda953493e.png?v=1780071692","url":"https:\/\/shop.masterspaswest.com\/collections\/21ft-swim-spas.oembed","provider":"MasterSpas West","version":"1.0","type":"link"}