This 8 Inch Heat Sealing Machine provides sturdy, airtight, watertight seals for polyethylene (PE) and polypropylene (PP) bags and some other materials (shrink film, saran, etc.) NOT recommended for use on cellophane, foil, metalized, Mylar, etc. These 8" sealers only use power and get hot when the seal arm is depressed to seal bags. They cool immediately after sealing. 8 Inch Heat Sealing Machines have a solid state timer adjustable from .3 second to 1.2 seconds for sealing bags of various thickness (Max 6 mil. for PE, max 4 mil. for PP). These machines are sturdy yet lightweight and easily transport. 110 volt standard for this machine.