44-33 Eco-Everflex Sealant is a specially designed non-hardening, fire resistant, water based sealant. Because it is water based it has no offensive solvent odor and is safe to use in occupied areas. This sealant is easily applied by pump or hand extrusion. It does not string or web during or after application. Eco-Everflex Sealant is ideal for sealing Snap-Lock or Pittsburgh Seams on HVAC ductwork. It is suitable for inline application. Because of its high solids, low shrinkage, and Everflex properties, 44-33 is also used as an acoustical sealant. It presses into voids and gaps between studs and floors and remains flexible to seal these areas against noise penetration during expansion and contraction.