Urinal deodorizer blocks, cakes, and pucks offer an effective means of odour control in restroom cleaning. Some blocks contain para, and some newer styles are para-free. Urinal screens fit over the drain and release fragrances. Some have fragrances infused into the plastic, and others hold the deodorizer block inside the plastic screen. The screens reduce splashing and prevent the urinal blocks from falling into the drain as they dissolve.