Shape

The shape of the Prime is commonly described as an EC2-type shape, which isn't wrong, but not quite right either. The best comparisons I can come up with are the ROCCAT Kain series and SteelSeries Rival 310. The Prime has the narrow front and right-side back flare of the Rival 310, along with the flattish left-side profile of the Kain. The way the left side is significantly raised, with a centered hump that slopes down gradually towards both ends, then is reminiscent of the EC2. The overall profile is bulkier than that of the EC2, somewhat similarly to the VAXEE Outset AX. Lastly, the back portion and how it integrates into the left side is not unlike that of the Rival 3/Aerox 3. As you can see, design elements of all kinds went into the Prime, forming a familiar yet somewhat unique shape. The main buttons feature fairly pronounced comfort grooves.

Much like on many previous SteelSeries mice, the sensor is shifted towards the back of the mouse. Though not as pronounced as on the Rival 3/Aerox 3, the sensor still is positioned below the thumb level. Neither necessarily good or bad, this is, rather, just something that requires some getting used to.


As for grip styles, I'd say the Prime is mostly suited for palm and claw 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 Prime very comfortable in claw grip.

Dimensions

This table includes the dimensions of the SteelSeries Prime 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:


Pulsar Xlite


ROCCAT Kain 100


Glorious Model D


SteelSeries Rival 310