Provent-a-Mite etc. (permethrin sprays) are designed to kill and prevent reptile mites and ticks.
Permethrin is a pyrethroid insecticide which is used to control a variety of insects - from mosquitos, to human scabies and head lice, dog fleas etc.. Pyrethrin insecticides were developed by isolating chemical compounds found in the Pyrethrum (Chrysanthemum) genus of plants. Permethrin kills insects by affecting the insect's nervous system after they touch or eat it.
Reptile mite products like Provent-a Mite are permethrin products which were developed specifically for use with reptiles. Provent-a-Mite contains .05% permethrin.
Provent-a Mite and other permethrin sprays are to be used only on the habitat substrate, racks etc.. Permethrin sprays cannot be sprayed directly onto the animals themselves, and the animals must not be present in the habitat until the permethrin spray is completely dry and any fumes have been vented.
Once dry, reptile permethrin sprays have varying lengths of duration. Some, reptile sprays, like Provent-a-Mite, claim they provide long-term residual protection and can prevent mites and ticks for up to 30 days. Longer lasting permethrin sprays are able to kill larval mites and ticks.
Provent-a-Mite is US EPA and USDA approved for use with all species of reptiles, including tortoises. Other permethrin sprays may be appropriate only for snakes.