it cant be a regular old float, or a sight glass. basically what we are doing is trying to remove the risk of operator-error on some atomizing air equipment (more or less compressors) because people tend to forget to add oil. this 'gauge' (which is more like a switch really) needs to send a low signal to a cut-off switch once a certain low level of oil is reached. obviously it needs to be explosion proof because electricity is being used and it is just kind of hanging out in a giant pit of oil. also the casing needs to be able to withstand constant 100psi pressure in the crankcase. maybe even 150 if that's possible.