14 is plugged with a threaded plug 16 and various feedthroughs for electrical conductors 17 are installed in the plug 16 the number size and position of the feedthroughs can be varied the conductors 17 are pressure isolated by the plug 16 and the feedthroughs preferably the feedthroughs provide hermetic sealing so that pressure isolation is sustained the spherical body 13 serves as a knuckle which is gripped by the surrounding socket to be described while rotation is permitted sealing is also accomplished on the outer face of the knuckle 13 an encircling ring or groove is cut in the knuckle 13 the groove receives a lip seal 19 to assure that the interior of the tool 10 is pressure isolated the knuckle is formed with a lengthwise groove 20 which is preferably duplicated at two evenly spaced locations the groove 20 extends along the length of the knuckle parallel to the passage 14 the groove has sufficient depth to receive a guide pin 21 the guide pin 21 has a width and radial inward extent enabling the pin 21 to move along the length of the groove 20 but movement in the trasnsverse direction for the pin 21 is forbidden moreover the total travel length of the pin is limited by an inscribed angle which relates to 30 u00b0 rotation the flex joint of the present invention permits 15 u00b0 rotation to both sides of a centerline axis or a total of 30 u00b0 deflection this is a scale factor which is acceptable in most applications and is believed to be sufficient to enable the tool 10 to be used in practically any circumstance the pin 21 is supported by a surrounding socket system as will be described the opposite end of.