Sto BTS Xtra is a one-component,polymer-modified, cement based dry powder material used as a lightweight adhesive, base coat and leveler in StoTherm® insulated wall claddings, and in StoQuik® Silver Cement Board Stucco claddings. It can also be used as a lightweight leveler or skim coat on concrete or masonry wall surfaces, including AAC (Autoclaved Aerated Concrete).