The N50 odor eliminator is a good match for the PURAMAX automatic self-cleaning cat litter box. You will get 6 individually wrapped Odor Eliminator tablets, each tablet can be used for up to 30 days, individually wrapped for effective long term storage. This odor eliminator has an expiration date of 24 months and can be kept for a long time as long as the individual packages are not opened. The Odor Eliminator is easy to replace and is the right size just open the box and put it in and it's ready to use. Purify the air, effectively remove odors, ammonia removal rate up to 95%. N50 odor eliminator is specially designed for PURAMAX automatic self-cleaning cat litter box. It can effectively control odor.