Power Meter V2

Specification

 * Power Level: -20dBm up to +30dBm
 * Calibrated Frequencies: 35, 72, 433, 868, 915, 1200, 2400, 5600-6000MHz in 50MHz steps
 * Accuracy: +/- 0.5dB
 * Attenuator: 30dB (Internal)
 * Battery: 3.7V Lithium Ion cell, 10440 size, 600mAh
 * Current Consumption: ~35mA
 * Battery Life: ~8 hours

Link To Product
Link : https://www.immersionrc.com/fpv-products/rfpwrv2/