Protects drain and deodorizes in one step. Pliable screen traps debris. Effective and economical para deodorizer lasts up to 30 days. NSF/USDA Classification C2. Dozen.Para block deodorants are air-activated, freshen the air, and eliminate undesirable odors. Made from paradichlorobenzene saturated with liquid deodorants. WARNING: This product contains a chemical known to the State of California to cause cancer.