3*4 Matrix Keypad Universal 3 x 4 membrane keyboard with the numbers 0 – 9 and the characters * and

Model Name: DC-DC step-down module Input Voltage: 4.5V ~ 24V Output adjust voltage: 0.8V~17V Output fixed voltage: 1.8v 2.5v 3.3v

MAX485 Arduino Schematic . Send or Receive from MAX485  

1S Li-ion 18650 Lithium Battery Charger Protection Board 4.2V 4A Specification Maximum sustained discharge current:4A size:4x35mm Package included 1 x