the bore within the gripper body 159 an annular gas conducting space 168 is present between the outer wall of the sleeve 60 and the inner surface of the bore in the gripper body 159 this annular space 168 ultimately communicates with pressurized gas distributed from the previously mentioned manifold 62 by way of a gas bore 170 that is connected to a fitting 172 screwed into the cylindrical gripper body 159 the previously mentioned coiled gas tube 64 connects the fitting 172 into a lower fitting 176 screwed into the distal end of the bottom plate 44 a short connecting tube 178 pneumatically connects the lower gas fitting 176 with a manifold gas fitting 180 which may easily be seen in fig2 a 2b and 2d as has been indicated previously a guide tube 185a 185f is mounted around the bottom ends of the cylindrical body 159 of each of the grippers 51a 51f to this end the upper end of each of the guide tubes includes an annular flange 187 that is secured around the bottom edge of the cylindrical body 158 of the grippers 51a 51f by means of mounting screws 189 as is best seen in fig2 a and 2b the bottom end of each of tubes 185a 185f includes a spring loaded detent 191 the purpose of the detent 191 is to secure a guide sleeve not shown which is detachably connected around the bottom end of each of the tubes 185a 185f for assisting the system operator in pushing the push cables 27 of each of the heater probes 3a 3f through the grippers 51a 51f the bushings 80a 80f.