MADE BY STRUTHERS ELECTRONICS AS A DIRECT REPLACEMENT FOR THE HP MODEL 478 THERMISTOR MOUNT. DESIGNED FOR USE WITH THE HP 432A POWER METER. 10 MHZ TO 10 GHZ FREQUENCY RANGE. 200 OHM OPERATING RESISTANCE. UNUSED SURPLUS. GUARANTEED FOR 30 DAYS. Availability: Usually ships the next business day. $125.00