Got this on a recent trip to the US - Super comfortable and ergonomic. Getting used to it took about ten minutes, and after that I was unstoppable. The hand rested on the Kensington logo area, and the fingers were comfortably placed on the rest of the device. Best bit was the fact that I did not have to move my arm or wrist around. The device also did not require a Mouse pad for smooth operation, and took up lesser physical space on my desk. Since it does not have to be moved around, you can place it at one comfortable position with respect to your arms and torso and use it in situ. This was about 30$, but the sore point was the absence of a scroll wheel. I also missed Middle Click, since I use that a lot to open new tabs when browsing. Kensington support software allowed to me to assign specific functions to clicking both Left and Right buttons together. So that functioned as a middle click option. However, scrolling was still limited, so that involved moving the cursor to the right of the screen and holding the scroll bar with the left button pressed and scrolling using the track ball. Cumbersome, but makes you realize how far we have come in mouse technology. Realized that for about 3150 INR or about 48$, Kensington makes a higher model, that comes with a scroll ring as well. Ordered thru FlipKart, was delivered in about 4 days. Having used the lower version of this track ball mouse, I found that the build quality was slightly plasticky versus the cheaper one. Also to accommodate the scroll ring, the buttons were smaller on the sides. Though the base was broader, had bigger anti slip pads. You can pop the track ball out by poking it from below. One good bit about this model was that the track ball does not pop out that easily. On the regular trackball model, you flip it over, and it falls. So a bit of a hassle if you're lugging that around in your bag. This, thankfully doesn't let that happen. The removable wrist rest. Initially it felt like cheaply finished plastic. But upon flexing it, found that instead it's PVC, rubber like, and pretty flexible. I used the trackball with and without the attachment. Honestly, I think the inclusion/exclusion of this attachment depends on the height of your desk, with relation to your elbows. If the desk is at a higher elevation, this helps. If it a low desk, then this really doesn't help much. But good to have as an add-on nonetheless. With the Wrist Rest attached. Comparing both next to each other. The regular trackball is now up for sale if anyone is interested. 20$ and get it!