Founded in 1926, Keystone Concrete Block and Supply Company Inc. produces and distributes a complete line of masonry products and supplies. Based in Scranton, Pa., the company offers general construction building blocks, as well as is the exclusive manufacturer of Versa-Lok retaining walls systems. It also sells a complete line of masonry supplies, cultured stone, concrete pavers and accessories. Keystone Concrete Block and Supply Company Inc. offers concrete pavers from Capitol Concrete and Cambridge. It offers masonry accessories and tools from Wire Bond, Grace, WR Meadows, Sure Kleen and Bilco.