ON SALE NOW: SAVE 20% ON ONYX COLLECTION SHOWERS & INTEGRATED COUNTER-SINKS. ONYX custom designed showers feature seating, a shower caddie and definitely no grout lines to clean. ONYX Integrated Counter-Sinks have an upscale look and can be custom designed to fit your space. See the beauty of ONYX today at Hilltop Lumber’s showroom in Alexandria. This is a limited time offer.