Culligan US-4 Adapter Compatibility
The Culligan US-4 is not compatible with pull-out or pull-down kitchen faucets (the faucet head retracts into the faucet body, and the attached filter housing would block retraction). For pull-down or pull-out kitchens, use an under-sink filter (APEC ROES-50, iSpring RCC7) with a dedicated faucet instead. The US-4 is designed for fixed-spout kitchen faucets (non-retracting) or bathroom faucets. Non-standard faucet aerator threads (Grohe, some TOTO models): may require a BRITA or PUR adapter instead of the Culligan adapter set -- test all included adapters before concluding incompatibility.