Don't count on
Waterproof Metal Detector can against big rain or even in water. Actually it's only partially waterproof. Professionally it's defined like IP55. You'd better use a tent to cover it.
Archway Metal Detector gate protect people's life from being hurt and property being damaged by terrorism. Chinese Walk Through Metal Detector is cheap but also good in use. And also offer 1 year warranty, it worth your choice! 
