As far as I'm concerned these reg covers are a useless waste of 30 bucks. first they're plastic so if anything hot hits them they're going to melt - as opposed the regulator themselves which are steel - i guess if something else were to fall onto your set up they might offer some protection but anything heavy enough to damage your regulator would prob cause bigger problems like damaging a tank valve so best if you take precautions for that not to happen in the first place.
but the worst part of the design is the cover sticks out about an inch from the face of the dial so you cant see the settings from any angle other than straight on. since every safety manual makes a point of not cracking tanks standing in front of them not being able to see the dials from an angle is less than ideal. plus when you're cutting unless you're at exactly the right angle you cant see gas pressure. personally, i like to check my ace pressure once in a while just to make sure i'm not about to blow myself up.
bottom line - a total waste