Compact Digital Voltmeter

Power on/off is possible in conjunction with ignition key.
Measures voltage of accessories or other supplies by changing red wire connection. 
Backlight changes to red when voltage become lower than 12V.
Double-sided adhesive sheet (30mm x 20mm) attached for installation.
 
• Body: L 42mm x W 25mm x H 10.8mm
• Backlight: White (regular) / Red (low) 
• Operating voltage: Direct current 7.5V ~ 18V