They work unattended for an unlimited length of time, although they need to be recharged by placing them in the sun every 6 months and soaking them in salt water, then rinsing thoroughly, once a year. Especially useful in musty basements, closets and sheds.
Made from a naturally occurring rock called clinoptilolite that contains ions trapped in micro-pores in the rock. Offered in two sizes. The smaller set of two 4 oz bags is particularly suited for use in small closets, a refrigerator or even shoes. The larger bag weighs 2 lb and treats approximately 4800 cubic feet of space.
Made in Canada.