This part of 60444 explains the test fixture that allows the accurate measurement of resonance frequency, resonance resistance, and equivalent electrical circuit parameters of a leadless surface mounted quartz crystal units using zero phase technique as specified in IEC 60444-4 and IEC 60444-5. An equivalent circuit constant and the application frequency range obtained by using the test fixture are then shown. In addition, this is applied to the enclosure shown in IEC 61240 as a crystal unit without lead wires. An equivalent circuit of the test fixture and an electric values are based on IEC 60444-1 and IEC 60444-4. The range of load capacitance is 10 pF or more. Calibration of the measurement system and CL adapter board is explained hereafter. This document applies to the test fixture that allows the accurate measurement of resonance frequency, resonance resistance, parallel capacitance C0, motional capacitance C1, and motional inductance L1 of the crystal unit over the frequency range from 1 MHz to 150 MHz using an automatic network analyzer, based on IEC 60444-5.