Shape

Contrary to what one may expect, it is not that easy to liken the shape of the MM731 to something that already exists. The best I can come up with is the MM530, though the MM731 is significantly smaller and differently balanced. The MM730 took some inspiration from the Microsoft Intellimouse Explorer, which is why the MM731 may be described as somewhat similar, but at the end of the day, the MM731 is its own thing. The right backside flares out quite a bit, whereas the curve on the left side is mostly related to the vertical axis, widening only at the bottom towards the back. Compared to other right-handed ergonomic designs, the left side isn't raised as much, and while the hump is centered, it is not as pronounced as on the EC series, for instance. The front also stays rather slim compared to the wide back, which is reminiscent of the SteelSeries Rival 310. The main buttons feature minor comfort grooves, more so on the left than the right one. Overall, a balanced design that handles well in practice.

Another point worth further scrutiny is the sensor position. Relative to one's thumb, the sensor on the MM731 is placed more towards the front. While this already was the case on the MM530, it is even more pronounced on the MM731. In fact, the sensor is placed as far forward as physically possible given the limitations of the design. Compared to the more common centered position, a more forward sensor allows for a wider wrist motion arc. At the same time, those coming from a mouse with a more centered sensor may need some time to fully adjust.


As for grip styles, I'd say the MM731 is suited for all three grip styles; i.e., palm, claw, and fingertip grip. It is a medium-sized mouse with a moderately pronounced hump, which should make it suit most hand sizes. For reference, my hands are 19 cm long and 10 cm wide, and I found the MM731 very comfortable in claw grip.

Dimensions

This table includes the dimensions of the Cooler Master MM731 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:


Glorious Model D Wireless


Pulsar Xlite Wireless


SteelSeries Prime Wireless


ASUS ROG Keris Wireless


Razer DeathAdder V2 Pro


ROCCAT Kone Pro Air