new and high quality Features: Exquisite workmanship, high efficiency, stable working performance. Premium material ensures maximum strength and durability for long lasting usage. Normally open type: When the magnet and the reed switch are together, they are in the off state (NO). Normally closed type: When the magnet and the reed switch are together, they are in the on state (NC). Used for Non-metal door/window protection External power supply, connect to wired or wireless alarm control panel. Magnetic Switch only, other accessories demo in the picture are not included! Tips: 1. Please do not use the door magnet to directly power on, or power on the equipment (such as buzzer, small speaker). 2. The power must not exceed 3W, otherwise the reed switch will be damaged. Specification: Model: MC-31B Material: ABS Power Supply: DC 100V/ 0.3A Color: White Dimension: 55x12x11mm/ 2.17x0.47x0.43in Quantity: 1 Set Note: 1.No retail package. 2.Please allow 0-1cm error due to manual measurement. plz make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 Set x Magnetic Switch