Easy to install on every type of door or window. The magnet goes on the door or window, and the sensor goes on the frame (or vice versa). Magnet can be placed up to 2 inches from the sensor, so sensors fit on all types of doors and windows. SimpliSafe sensors come with the battery pre-installed and adhesive tape pre-applied, making set-up a snap. : Compatible with a SimpliSafe security system : Fit on all types of doors and windows : Battery pre-installed Condition: New : We consider offers on some items. If you want to make an offer, actually make one. We do NOT respond to offers made via message or questions similar to "what is your lowest price". All heavy glassware must be purchased individually. Bundling may NOT be done with heavy glassware. Due to the weight limits set in Poshmark's shipping policy we will not be able to ship multiple glass items together. We will cancel orders of bundled glassware because of this.