Turn any size aerosol can into nonhazardous, recyclable scrap metal with these drum-mounted systems. They safely puncture cans to relieve pressure and drain residual liquid into the drum. To use, thread the puncturing unit onto the 2" dia. opening of a drum (not included); then thread the filter with replaceable carbon cartridge onto a _3/4" opening in the drum. Insert the can and push the lever to puncture.