150 GPD Flow Restrictor Rating: Select ratingGive it 1/5Give it 2/5Give it 3/5Give it 4/5Give it 5/5 Average: 5 (2 votes) (0 reviews) This Flow Restrictor fits into the black 1/4" Ro tubing where it enters the membrane housing, and should be matched to a 150 GPD membrane. $10.00 SKU: 22005 Necessary piece for your RO system to work!