DetailsPuROTwist 3 Stage 50 GPD RO Reverse Osmosis TFC Membrane Quick Change Water Filtration Retro Fit System. PT3000T50-SS-RK Quick change head with 50 GPD membrane, Q5621 carbon block prefilter and Q5633 GAC post filter. No tank, faucet or installation kit. Uses John Guest quick connectors that are very easy to install. Works in place of the ® DuPure or ® Rayne "-60" Pure Blue - ® Omnipure -60 "Q" Series systems shown in the photo.