The Detex ProxiPen is compact, lightweight, and easy to operate as it "autosenses"and reads Radio Frequency Identification (RFID) tags automatically withoug any external controls or moving parts on the unit.

   The electronics are buried in a shock-resistant polycarboniate housing, making the reader completely waterproof and resistant against heat, shock and hydrocarbons. 
Drop it in an oil barrel.  If you can find it, it will be just fine. 
Drop it on to concrete, it will not break.  (10' limit.)
The ProxiPen is ISO certified.