Boardwalk® Urinal Screen with Non-Para Deodorizer Block deodorizes, cleans, and prevents scale build-up within the urinal. Every flush of the urinal tints the water blue so the water is noticeably treated. The pleasant, scented block eliminates odors and helps to maintain drain lines by fighting bacteria growth. The flexible plastic screen traps debris to further protect the drain. Long-lasting, lasts up to 1,500 flushes.