The shape of the VT9 Air clearly resembles that of the Razer Lancehead, albeit with some modifications. Most notably, the hump on the VT9 Air is centered and gradually slopes down towards both ends, resulting in a flatter profile overall. The rear flares are present of course, and create most of the side curvature as the sides themselves don't curve inwards much, and the front doesn't flare out much, either. As a result, the VT9 Air doesn't provide as much palm support, but it also lends itself better to a 1-3-1 grip (i.e., three fingers on the top, two on the sides) than the Lancehead does. Lastly, the VT9 Air also lacks the comfort grooves present on the main buttons of the Lancehead.
As for grip styles, I'd say the VT9 Air is generally suited for palm and claw grip. It is a medium-sized mouse with a barely pronounced hump, which should make it generally suit medium-sized and smaller hands. For reference, my hands are 19 cm long and 10 cm wide, and I found the VT9 Air comfortable in claw grip.
Dimensions
This table includes the dimensions of the Rapoo VT9 Air and several other ambidextrous 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.
Rapoo VT9 Air Dimensions
VT9 Air
X2H (Size 2)
Aerox 3 Wireless
Atlantis 4K
XM2we
Base Length
11.0 cm
11.5 cm
11.5 cm
11.7 cm
11.6 cm
Length (including overhang)
11.97 cm
12.04 cm
11.85 cm
12.33 cm
12.2 cm
Front Height (lowest point)
1.0 cm
1.2 cm
0.9 cm
1.1 cm
0.9 cm
Height (highest point)
3.66 cm
3.91 cm
3.79 cm
3.80 cm
3.83 cm
Front Width (widest point)
6.08 cm
6.13 cm
5.88 cm
6.16 cm
6.16 cm
Back Width (widest point)
6.58 cm
6.50 cm
6.69 cm
6.59 cm
6.49 cm
Grip Width (narrowest point)
5.81 cm
5.97 cm
5.89 cm
5.96 cm
6.06 cm
Below are some comparison shots with each of the measured mice: