Features: 1.Square USB interface for stable connection. 2.Using imported high performance USB control chip. 3.Using special relay drive chip ULN2803, the relay works more stable. 4.Board power socket and terminal, two ways to access the power supply are convenient and flexible. When the power is connected, the relay can remain set even if the computer is turned off or the USB is unplugged from the computer. 5.Support for WIN7, for XP 32-bit/64-bit system. specification: Square USB interface for stable connection. Using imported high performance USB control chip. Using special relay drive chip ULN2803, the relay works more stable. Military grade PCB board production. Board power socket and terminal, two ways to access the power supply are convenient and flexible. When the power is connected, the relay can remain set even if the computer is turned off or the USB is unplugged from the computer. Support for WIN7, for XP 32-bit/64-bit system. : Type: Computer Control Switch Relay Module Input voltage: DC 12V Input current: > 300mA Wiring method: NC/COM/NO Relay size: about 7.5 * 10 * 2cm / 2.9 * 3.9 * 0.7in Package List: 1 * Relay Note: 1. This product can maximum control AC 250V, 10A AC load and maximum DC30V 10A DC load