The ET112-002 is a reverse osmosis water filter drain line adapter. It is designed to connect discharge 3/8-inch tubing from a RO filter to the drain. The ET112-002 is connected to the sink drainpipe to receive the reject water from an under-counter reverse osmosis appliance or a distillation system. The installation provides a reliable and trouble-free connection of the 3/8-inch discharge water tubing to the drain line. The ET112-002 is designed for residential and commercial use. The ET112-002 is the preferred way to connect RO system to the drain line. The ET112-002 eliminates gurgling sound and provides a safe and effective way to comply with all local plumbing codes. The ET112-002 drain adapter is listed by UPC and tested for compliance with IPC and NSF standards.