The TX-502 SWR and power meter can be directly read without any calibration Three color scale design to improve readability LED backlight provides smooth and uniform lighting A true directional coupler to improve accuracy beyond frequency. The personal instrument scale for each power range improves the accuracy of readings The -103 has a measurable power range of up to 200W Frequency range: 1.6 - 525MHz Centre calibration: 28.5/145/435MHz Power range: 0 - 200W Power scale: 2/20/200W Maximum power: 200W Accuracy: 10% of full scale or higher proportion (note: 20W/1260MHz) Insertion loss: Less than 1.2:1 (The product printed words depending on the batch, but this does not affect use) Testing function: electricity power, SSWR, PEP Impedance: 50ohms Connector: M-type Input power: 9 - 14VDC, 200mA Color: As Shown Material: ABS Package Contents: 1 * TX-502 SWR/Watt Meter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.