Specification:Display: 2-lines x 16-charactersBacklight: Blue with white character colorLCD controller: HD44780Pin Definition: VCC, GND,SDL and SCAContrast Adjust: PotentiometerBacklight Adjust: JumperDefault Address: 0x27 for PCF8574T chip; 0x3F for PCF8574AT chipWorking Voltage: 5V100% Satisfaction Guarantee12-Month Warranty; No satisfied ,Free reason for return; We could also resent you new one due to quality problem.Package:2 pack blue 16x2 1602 lcd display + I2C serial interface