Check the listing for details. 1 PCS 5A Hall Current Sensor Module ACS712 Module. Condition: New. Listed at 3.99 USD. Description:1. current sensor chip: ACS712ELC-05B;2, pin 5V power supply, on-board power indicator;3, the module can measure the positive and negative 5 amps, the corresponding analog output 185mV / A;4, no current flows through the detection, the output voltage is VCC / 2;5, PCB board size: 28 (mm) x13 (mm)- Many customers ask if they can ship their products in a paper envelope. Unfortunately, we cannot do that because merchandise needs extra protection, and USPS does not provide a tracking number for this type of service.- The shipping service we offer is First-Class Package Service, which is a domestic mail service offered by USPS. It is designed for mailing lightweight packages that weigh up to 15.99 ounces and offers delivery in 1-5 business days. It includes a tracking number, allowing customers to track their packages. USPS prices start at $4.75, but we don't have any control over shipping prices.