..... All bottles must be securely mounted (may not use plastic brackets), stamped with minimum DOT-1800 pound rating, and identified as nitrous oxide. Nitrous oxide bottle(s) located in driver compartment must be equipped with a relief valve and vented outside of compartment. System must be commercially available and installed per manufacturer's recommendations. Commercially available, thermostatically controlled blanket-type warmer accepted. Any other external heating ofbottle(s) prohibited.