The device supports 2G mobile phone cards and IoT cards, but does not support CDMA mobile phone cards Select GSM network nano sim card, need to open GPRS Internet access function and caller ID Insert the sim card into the device (there is a schematic diagram of the direction on the card holder), and hold the power button for 3 seconds to Three lights are on (the black button next to the deck is the power button) Power on: and hold for 3 seconds SOS: and hold for 3 seconds in the power-on state Power off (with sim card): long for 10 seconds Power off (no sim card): long for 3 seconds Due to different batches, the appearance and color of products may be different, which not affect the use Colour: Black Material: PCB Package Contents: 2 x Module 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.