1. Use PIC16f628a microcontrollers 2. Do not need batteries - powered from the ignition 3. Standard FUTABA plug(Black-Negative Red-Positive and White-Signal) 4. Uses high-brightness LED digital tube. 5. Input voltage range:4.8V-12.0V 6. Current consumption 25mA-60mA 7. Mini tachometer indicates up to 30000 rpm 8. Actual RPM= Display Digital *10 9. Body Size: 41mm L x 17mm W x 12mm H 10.Window Size: 30mm L x 15mm H 11.Weight:8.5g (0.3OZ)