CHUYI Vertical Ergonomic Wireless Mouse - Rechargeable Silent Mouse with 3 Adjustable DPI (800/1200/1600) for PC, Laptop & Notebook - USB Receiver Included - Right-Handed Design (Black) - Perfect for Office Work, Gaming & Long Computing Sessions

Arrived with something already rattling inside. Of course, the mouse was in a plastic bag/sleeve, inside a small box, with no padding, inside a larger Amazon box, also with no padding. Of COURSE something made of cheap plastic will break off inside. It seems still to work, though.This mouse comes with no instructions. Because you need instructions to use a mouse?Ergonomics:The fit is weird when you're used to a regular mouse. I've had this only a day and a half at work, so about 12 hours' use, and it's ... well, it's okay. For the price, yeah, great. But it's weird to hold.I found that I had to go back to my old mouse today for one simple little motion because the vertical mouse just couldn't move slowly or precisely enough. I may need to adjust rates in Control Panel, but even then it won't change how the buttons hit the fingers when trying to more precisely control the cursor. Especially small, precise motions, which are often required when selecting lines of text or placing items in a workflow, are more difficult with this mouse when compared to the regular.This mouse actually is larger-feeling than the regular, yet my hand naturally falls with my index finger slightly high for the left button. This isn't bad: I can choose whether to use the index or the middle finger for the left button. It's an option I don't dislike having, though I prefer the "usual" index.It fits the hand well enough, until you reach the edge of the desk and need to lift-and-reposition. The regular mouse I merely pinch with my thumb and pinky, but with this one, that resulted in a right-click about 70% of the time as the mouse slid out from my grip (until I became more familiar with how to grip it)(no, that's not a euphemism). I have already learned to "twist" the mouse along the longitudinal axis (i.e. keeping the right edge of the mouse on the desk) until the "eye" no longer detects motion on the desk. Doesn't take much, maybe 25-30 degrees of tilt.I find that I still am moving my wrist, though not as much, with this mouse. If I could learn to move my entire arm (the way fountain pens used to be taught to early writers -- write the letters with your arm, don't draw them with your wrist) then maybe it would be better, but I've tried doing that, too, and it's just weird.I *WILL* say that my carpal hasn't bugged me today, but that comes and goes *anyway*. I can't say for certain that this mouse has anything at all to do with that. Oh, wait a minute... yeah, no, I feel it again... maybe I'm typing too much...Other Physical:It's about as heavy/light as a regular OEM mouse from a major computer distributor. This can be a good or bad thing.The cord could be longer. This, too, could be a good or bad thing. It reaches my desktop PC, but only barely, and wouldn't if the PC were under the desk instead of on top of it. The OEM mouse has a cord that's at least a foot and a half (maybe half a meter) longer, and can easily be tucked away to the back edge of the desk (and hidden) whereas this one crazily zigzags diagonally to the back of the PC.Also, I have found that the skid pads on the bottom tend to grip the plastic-topped mousepad I use. I have to use the mouse directly on the desk to avoid having to break friction to get it to move. It wasn't much friction, but just enough to notice and be distracted by.It's very quiet. I don't hear the buttons click at all. Definitely feel them. Tactile response is decent -- not the best, but it is definite tactile response.Scroll wheel is... well, odd to use. Takes getting used to. I'm still not there.Browser buttons are worthless. They work, or at least one of them does (back). The other (forward, presumably) didn't do what I expected and what it DID do I don't recall. It was annoying enough I've learned already to avoid them. I don't know what the button behind the scroll wheel is for. It doesn't seem to do anything. Perhaps this is because of the thing that's rattling around inside? I don't know; what's rattling sounds small. Still, this is what the instructions you don't need for using a mouse would be handy for.Onscreen:The movement of the cursor using this mouse is somewhat ... inaccurate is the wrong word... It's like calling for a guided missile and getting a strafing run instead. Or you want a rifle and instead are handed a grenade launcher. Or you want laser guidance and get heat seeking. Or no seeking. >shrugs