1. When the DC power supply end has power, power supply is preferred. 2. When the DC power supply end has no power, it automatically switches to battery power supply. 3. When the DC end (power adapter or power switch, etc.) has power, it is preferred to power the load. 4. When the DC end (power adapter or switching power supply, etc.) has no power, it automatically switches to the BAT end (battery end) to power the load. 5. Note: There be a power outage of 0 seconds when switching. Product name: Power failure automatic switching module Product model: X804 Applicable voltage: DC 12V-48V Product load: 10A Installation size: 23mm (2 holesx3mm) Due to different batches, the appearance and printed text of the product , but it not affect the use Colour:Blue Material:plastic Size: 50mmx 30mmx18mm(lengthxwidthxheight) Package Contents: 2 failure automatic switching 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.