Works great. No batteries and no screw to hold back plate in. 
The Protimeter Surveymaster Moisture Meter is a digital portable hygrometer that measures humidity levels in plants and soil. It features a sleek gray and yellow design, with a digital display for easy reading. The electric measuring technology provides accurate results, while the compact and portable design makes it convenient to use in various outdoor environments. Constructed with durable plastic and metal materials, this moisture meter is a reliable tool for yard, garden, and home maintenance.r