For cleaning gunite pools with a hard-surface finish, Poolmaster's 18 in. Aluminum-Back Combo Bristle Brush features a die-cast Aluminum back and handle for superior strength and a blend of stainless steel and Nylon bristles for extra cleaning strength. For use with standard pool poles. NOT FOR USE on vinyl liner pools. 1  For cleaning gunite pools with hard-surface finish. 2  Combination of durable Nylon and stainless steel bristles. 3  18 in. die-cast aluminum back and handle.  DO NOT use on vinyl liner or fiberglass 1  surfaces. For use with standard pool poles - sold separately.