Torque Wrench Maintenance

[Mossyoakglock]

I have a cheaper inch lbs torque wrench that use for smaller stuff on my truck. It has a small clear plastic cap on the side of the tube about mid way between the head of the wrench and the adjustment handle. I can't find the owners manuel on it anywhere to see what the hole is for. I want to say it is for some sort of oil or lubricant to keep the wrench in proper working condition. Is that correct? If it is, what type of lubricant should I use?

[Nytemare]

Its probably where the adjustments are done...little set screw inside there. You cannot adjust it though. It has to be sent to a calibration center...with my job in the Navy...this is one of my many secondary duties...to send stuff out for calibration every year...like torque wrenches, multi-meters O-scopes...etc.