Adjustable electronic timer controls heating duration to properly seal polypropylene and polyethylene bags up to 6mil thick. No warm-up required. Flat element sealer with cutting blade creates super strong, tamper-evident seals. Just press down armature to seal, then slide the built-in cutting blade to trim. Blade cuts within 1/4" of seal and a short tail flap remains. Flat element sealer does not melt through bags. Not recommended for sealing material thicker than 6 mil.