Hydron TW-1812-50D Dry RO Reverse Osmosis Membrane - 50 GPD A cost effective replacement membrane that offers consistently high quality and performance. This membrane can be used to replace CSM, Axeon, Dow FilmTec, GE, and any other 1812 style membranes Thin film composite - superior rejection and flow rates, bacteria resistant 50 gallons per day - production rate under ideal conditions 95-97% Rejection Rate Industry standard size fits most reverse osmosis systems - Approximate dimensions 11-3/4"L x 1-3/4"D