OK-I mounts behind the faucet spout. It remains out of the way for everyday faucet use. However, the OK-I is always there as a permanent eyewash station when needed. There is no plumbing required. The OPTI-KLENS unit installs easily onto any faucet, in any sink, or basin. Two of the most common adapters are packed with the unit. If another adapter is needed, a free exchange is offered. No professional installation required.