NOS systems are calibrated for optimum performance with a bottle pressure of 900- 950 psi. The pressure will change with temperature. Heater kits are thermostatically controlled (except P/N 14169NOS, which is pressure controlled) to keep the bottle at correct pressure. Kits available for the most popular-sized bottles, with both 12-volt and 110-volt heaters offered. Nitrous Bottle Heater for 10 & 15 lb Bottles 12 Volt DC w/ Thermostat