Urinal Toss Block with blue dye can change the perception about your bathroom with its strong odor control. If the restroom doesn't smell clean, the customer won't perceive it as clean, and that can affect business right down to the bottom line. NoRoma technology combined with billions of enzymatic bacteria breaks down organic materials and eliminates odors at their source. ParaFree deodorizing block contains cleaning agents to keep surfaces clean. Blue dye shows the block is doing its job. The 3 oz. block is enclosed in water-soluble wrap. It can be used with Impact 501 Urinal Screen that has a block holder.