Plastic City Recessed Water Fill with 1/2" FPT Brass Check Valve (A01-0176LF) by Valterra. With this top-grade product, you’re sure to keep your next camping van trip fresh and clean. It’s intended to prevent or stop any leaks your camper may have and thus keep your plumbing flowing smoothly. The product is fabricated from wearproof materials that are resistant to rust. It’s designed with high precision using leading-edge equipment to last for the long haul.