To be fitted to the LOW pressure side of a 3000psi or 4500psi air bottle.

Please note, air burst disks are not the same as Co2 burst disks. If a 1.8K (Low pressure side) burst disk fails, it's because high pressure air from the bottle is bypassing the reg seat. If you simply replace the burst disk, you have not fixed the problem and the disk will just burst again.

A blown 1.8K burst disk is an indication of a problem with your reg (It's usually dirt so make sure you fit a fill nipple cover). Always seek professional help when dealing with a high pressure regulator.