I believe these have a parasitic battery drain - VISM Flipdot Pro Red Dot Reflex Optic

What's going on with this red dot? My batteries keep draining without using it. Is there a parasitic drain with these? Has anyone else had this issue? VISM Flipdot Pro Red Dot Reflex Optic I've had this mounted on one of my Glock's which I don't use very often and after just a few months of my gun just sitting without being used at all the battery in this red dot drains all the way down. I highly suggest to look for other red dots if you're serious about getting one. I love the idea of these with the flip up part of them so they don't take up much extra space but if they are draining the battery without even using the red dot what's the point? By the time you actually want to use the sight it's dead. Also the sight window is very small so it's very hard to even see the red dot a lot of the times.