Premium mice with a premium price tag should get as much protection as possible, and Logitech knows this well. The PRO Wireless comes in a stylish, thick box with a mold in its upper and lower part that protects the mouse from impacts during shipping and handling. There is no flap you can swing open or any plastic covers; once you open up the box, you can instantly get your mouse out. The accessories are beneath the bottom mouse holder. The contents of the box are the mouse itself, a cable, wireless transmitter, some instruction manuals, and the modular side buttons and their covers.
The Logitech PRO Wireless features a rather simple, but very well-made shell design. At first glance, you can see that it is fully ambidextrous, so both right and left-handed users may find it comfortable. If I were to compare it to existing mice, it would probably take its place between a SteelSeries Sensei and Zowie FK1, but it may be slightly taller and a tad shorter than both of them.
The sides are curved inward in order to help with lifting up the mouse. This is a feature that should have been included in the G Pro and its similar versions in my opinion, as they were often described as soap bars because of their outward curves. The main buttons are grooved as well for more comfort. Since we're talking about a pretty low-profile mouse, it is mainly targeted at claw and fingertip grippers, but I am pretty sure many will be able to palm grip it comfortably too. Everyone is different, everyone has different preferences, so it is impossible to tell for sure.
As for the dimensions, the PRO Wireless is 125 mm (4.92") long, which is about average for gaming mice. The width is 63.5 mm (2.5") at the widest part, but the actual width of where you would grip the mouse is a couple of millimeters less. The PRO Wireless is 40 mm (1.57") high at its tallest point, and the hump is in the middle.
ComparisonsHere are some shape/size comparisons with other mice:
Dream Machines DM1 Pro S
SteelSeries Rival 110