STI's 2 in. SpecSeal® Cast-in Firestop Device Extension Kit is intended for new-construction applications where cast-in firestop devices are installed before the concrete pour. When additional slab depth exceeds the base device range, the extension tube provides a practical way to increase the configurable device height without core drilling after the pour. The SpecSeal Cast-In system combines a sleeve, concrete form, and firestop function to simplify penetration preparation, while the extension accessory allows the system to accommodate greater concrete thicknesses. CD201EK is listed at 0.2 lb. per unit and is supplied individually, with a 12-unit case quantity.