features: 1. Based on the design of for 40PIN GPIO interface, for series motherboard 2. Equipped with dual core ARM M0+processor, the operating frequency is up to 133MHz 3. On board PCF85063 clock chip can accurate time 4. Onboard MP28167-A voltage rise and fall DC-DC chip, which can fast load transient response On board custom key, which can be used for raspberry pie power on, safe shutdown or other customized functions Protection circuits such as anti reverse connection circuit and anti reverse flow circuit of on-board battery stable and safe operation Onboard voltage and current detection circuit can detect the working voltage and current of raspberry pie in real time Specifications: Main control chip: RP2040 Communication interface: UART+GPIO Communication rate: 115200bps by default (other rates can be set programmatically) Power supply mode: USB interface or PH2.0 interface USB interface voltage: 5V PH2.0 interface voltage: 3.3~4.2V (3.7V lithium battery) Built in circuit: battery anti reverse connection circuit, anti reverse flow circuit, current and voltage detection circuit Product size: 56.5 x 65.0mm Diameter of fixing hole: 3.0mm color: blue : PCB+Metal Package Contents: 1 control board 1 x battery 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.