The 5800 Series of door and window transmitters provide the most reliable, convenient and cost effective solutions for security protection. These devices are powerful and versatile enough to help solve even the toughest, most labor intensive installations. This two zone transmitter has built-in magnetic reed switches and wired closed circuit contact loop. With a demonstrated outdoor range of over a mile, the 5800 Series has the best performance of any transmitters available today.This is for a pack of 4-pack of spare magnets and spacers for the 5816 Door/Window Transmitter. No actual transmitters come with the pack. These are replacement magnets.