Probe 2
Probe 2 : A device which can be brought into contact with, or inserted into, a system to take measurements on the system; normally designed so that it does not disturb the system significantly. May be a small tube with a sensing element of electronic equipment which can be lowered into a borehole to obtain measurements and data. (2) (Oil) Any electrically conductive object or piece of apparatus introduced into a tank which may increase the electrical field strength in its vicinity, for example, metal ullage tapes or metal sampling equipment. (IOTTSG)