Shape

The shape of the X12 is rather odd. Being symmetrical instead of just ambidextrous, the X12 has side buttons on both the left and right side. The symmetry extends to the thumb rest as well, which is curious in that thumb rests typically are only encountered on right-handed ergonomic mice, where one on the left side is never misplaced. On the X12, having a thumb rest on both sides inevitably feels alien as it'll effectively turn into a pinky rest of sorts. To be fair, the thumb rest in a way acts more like a flattened rear flare as opposed to a typical thumb rest, though it is too big to pass for a flare, yet too small to pass for a fully fledged thumb rest. Aside from the thumb rest, the shape narrows towards the back, resulting in a lack of palm support as the hump is centered. The front neither narrows nor widens relative to the middle, though it does get slightly wider towards the top. Overall, a very weird, uncommon design, and not exactly one I would call ergonomic or comfortable. The only somewhat similar shape I can think of would be the Razer Lancehead, though that one is flatter and has its hump more towards the back, whereas the X12 has more of a medium profile.


As for grip styles, I'd say the X12 is mostly suited for palm and claw grip. It is a medium-sized mouse with a somewhat pronounced hump, though space for the fingers at the sides is limited, which is why it is not necessarily suitable for larger hands. For reference, my hands are 19 cm long and 10 cm wide, and I found the X12 rather uncomfortable in claw grip.

Dimensions

This table includes the dimensions of the EVGA X12 and several other right-handed ergonomic mice. "Front height" denotes the distance between the base and main buttons. Measurements with two decimals have been taken with a caliper, while those with one decimal have been taken with a ruler. For a full list of all measurements taken, please refer to this sheet compiled by an esteemed community member.


Below are some comparison shots with each of the measured mice:


Mionix Avior Pro


Razer Viper 8K