{HEAD ~ Other sensors} can use LEDs tuned to {TAIL ~ frequencies} which are absorbed in different amounts by the gases typically used for welding 
{ HEAD ~ Other sensors } can use LEDs tuned to { TAIL ~ frequencies } which are absorbed in different amounts by the gases typically used for welding
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH