The probe (3) has a test prod (12) with a proximal end connected to the body of the instrument by a lead (11) with a covered section (11b). A handle (13) protects a section which forms a connection between the test prod and lead and which seats tightly on the proximal end of the test probe. The handle has a grip (43) which holds the distal end of the covered section of the lead and has a stress relief section (36) firmly secured to the grip to prevent the lead being pulled out of the handle.
