Mtp opti-flow 380 series direct acting pressure relief valve and vacuum relief valve, or breather valve are special types of relief valve which are specifically designed for tank protection.Re We offer a free valve sizing service, let us advise you on the best solution for you tank The valves are available in a number of combinations illustrated below. Click on any for more information Pressure and vacuum breather valves Presure only breather valves Vacuum only breather valves Spring loaded relief valves Pilot operated valves All of the above combinations are available in a range of sizes and can have flanged outlets or vent to atmosphere on both the pressure and vacuum depending upon your requirements. These are some of the options available for our breather valves. Available in aluminium, cast iron, carbon steel, stainless steel & other metals upon request Valve sizes from 50mm (2ì) to 300mm (12ì) We will line and coat valves if this is required Valve sizing available, let our software do your valve sizing and recomend your solution Flow curves available for all our breather valves, Full range of breather valve spares available Breather valve servicing and resetting available upon request