Features:
Although they don't outright label it as a notebook or desktop mouse, I'm going to call it a notebook mouse based on the compact size and the included carry pouch. That being said, the RM-8500 is a slightly larger than regular notebook mouse. Visually it has an entirely black finish with gray accents on some of the buttons and the area surrounding the scroll wheel. For better grip, each side of the mouse is slightly rubberized (although I could barely tell the rubber apart from the plastic body). This medium sized mouse is very comfortable for every day use on a home PC but small enough to take with you when you are mobile with your laptop as well.

(You can see a small low-battery indication light on top of the mouse behind the scroll wheel)

On the left side of the mouse you'll find both back and forward buttons which is nice to see because I find a lot of smaller mice will only have a back button. On top of the mouse is the usual array of buttons; left, right and middle click by using the scroll wheel. The scroll wheel itself reminded me a lot of my Logitech MX Revolution mouse, it's a large metal scroll wheel with a rubber ring around the middle. Although it doesn't have the free-scroll option of my Logitech mouse, it does have a nice, firm click-to-click action.

Flip the mouse over and you'll find a small power switch, the laser sensor and a plastic door that pops off to reveal the battery compartment. The RM-8500 is powered from one AA battery - Rosewill does not state an average battery life for this mouse though. One thing I was surprised not to find on the bottom of the mouse was some form of storage compartment or clip for the nano USB receiver. Almost all portable wireless mice have some method which allows you to store the receiver on the mouse, because we all know how easy they are to loose! Even if it is implied that it should be left in the USB port because of it's very small size, I still wouldn't mind having a safe way to store it when it's not in my computer.

Pictured below is that nano receiver I speak of - measuring a mere 1.5cm long! It operates in the 2.4GHz band and Rosewill states that you should get 360 degree, 10 meter coverage from it (this is significantly more than you'd get from a cheaper 20MHz wireless mouse).

On a more technical note, the mouse has a fairly high DPI of 800/1600. The ability to switch between the two DPI settings on the fly will make this a very versatile little mouse!