Easy to connect, only need to connect to the receiver then can telemetry module voltage, no need flight controller or other external equipment and parameter settings. Telemetering module voltage to avoid battery overworking. Mini dimension,make PRM-01 't become your drone's burden. Compatible transmitter AT10II/AT10/AT9S Pro/AT9S/AT9, easy to connect with R12DS, R9DS (Old version receiver: R10DS, R10D, R9D). PRM-01 telemetry module is compatible with 1 cell to 6 cells battery(3.7~25.2V). Please note: This telemetry module for Airplane, Aircraft voltage transmission on transmitter's display, is applicable to AT9, AT9S, AT9S Pro AT10 or AT10II. When paired with flight module PRM-01, model voltage is displayed. Configurable sound/message/vibration alarms signal potential problems when low model voltage. A low model voltage alarm value can be customized. Color: As Shown Material: plastic Package Contents: 1 x PRM-01 module 1 x Cable 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.