Reverse connection protection, and there are only two wires, easy to connect and operate. LCD display with blue/green/white backlight. Equipped with PVC film, the surface is waterproof. Built with buckle, no screw installation. Power-on indicates power percentage and visually indicates remaining battery. Specification: Type: Battery capacity blood pressure monitor Material: HTN / PCB Weight: approx. 13.7g Size: approx. 4.3*2.3*1.4cm Standard voltage: 12-48V Scope of application: battery or devices with battery Working temperature: -10 -50 Charging time: depends on the corresponding battery Note: 1. Please allow slight error due to manual measurement. 2. Different monitor colors may be different. Thank you for your understanding. Shipping quantity: 1pcs