Gates Part Number 74200507 Free UPS Ground Shipping within Continental US. The Gates U-507C Sonic Tension Meter comes calibrated from Gates. Gates 507 C (74200507) Sonic Tension Meter measures belt tension by analyzing the harmonic characteristics of a vibrating belt. The Gates Sonic Tension Meter comes with the meter and the standard cord Sensor. Other additional accessories include the flat flexible sensor and the inductive sensor.