Does the faucet 889 855 require a drain water restricter or is it built in? RO system!

http://www.homedepot.com/catalog/pdfImages/7b/7b7d77fb-d8f4-4e55-a91e-52cd027b5eb8.pdf


3. If the filtration system used is a simple system with one outlet and is not a reverse osmosis system that requires a drain, then skip to step 4.If a drain line is required to run through the faucet's integral air gap for a reverse osmosis(RO) system, connect the 1/4" drain line from the unit to the smaller barb on the the bottom of the faucet. Connect the 3/8" line from the faucet to the drain. This drain line works by gravity. Make it as short and straight as possible, with no dips or loops. (Fig.3)4. Thread the 3/8" quick connect adaptor onto the end of the stud and tighten securely. Connect the3/8" water line from the filtration system by pushing the line into the 3/8" quick connect adaptor.Pull down on the 3/8" line slightly to ensure the quick connect fitting has engaged. (Fig.4)

Seems it's built to be adaptable for whatever system you have. Not sure if this answers your question completely, and if not let me know.