HT630ED - 18.5" x 22.5" x 6" - 8 US Gallon Capacity. Left End or Bottom Drain - RV waste holding tank, available with a 3" spigot fitting and 4 level sensors installed. Constructed of tough ABS plastic for long service life. All seams are solvent welded and have a 1 1/4" mounting flange. This tank typically ships within 2 business days. Looking to mount a toilet directly on top of this tank? Take a look at the re-enforced version: a>Holding Tank Bottom Drain HT630BSBD. Handles both black & gray water or a combination of both in the tank Certified to IAPMO/CSA standards Upgrade, increase capacity, or replace a leaky or damaged tank with an industry leading quality ICON tank | Icon Technologies Holding Tank, HT630-ED, 22.5x18.5x6, 8 Gal. | ABS Plastic