Need to replace or add a waste tank to your RV, trailer, camper, or boat? This Class A Customs 31-gallon black water holding tank (model WT-3100) is built tough in the USA. It's designed to handle sewage and gray water, with sturdy construction that resists odors and corrosion. The tank is brand new in its original packaging, ready for installation. At 31 gallons, it's a good size for smaller to mid-size RVs or as a secondary tank. Use it for black water (toilet waste) or gray water (sink/shower runoff) – just plumb it in with the appropriate valves and fittings. Made from high-density polyethylene or similar durable plastic, it's lightweight yet strong. Perfect for DIY camper conversions, trailer upgrades, or replacing a cracked old tank. UPC 7426933331241. Whether you're a full-time RVer, weekend warrior, or building a custom rig, a reliable waste tank is essential for comfortable, sanitary travel. This one comes from a trusted brand and is made right here in the United States.