Stainless steel housing is very durable & will not rust. Aluminum cup maintains ideal temperature for vaporization. Holes in base allow natural convection action & unrestricted air movement. 5 foot grounded power cord. Proprietary PTC heating element has no moving parts. It provides consistent reliable warming. Suspend with jack chain at least 3 ft away from any combustible surface. Use only with properly registered materials. Follow all safety and licensing guidelines where applicable.