Surface and Materials

The surface coating on the top shell seems to be a soft-touch rubberization, which feels great in the hand. The separator panels on the side joints are glossy, just like the middle panel that contains the CPI switch and scroll wheel. The latter has a very nicely textured rubber finish, which just makes the scroll wheel fantastic to use overall.


Moving to the sides, the left panel has a slightly textured rubber overgrip. It provides a lot comfort and traction, and you probably won't have to worry about the mouse slipping out from under your grasp even with sweaty hands. As for the other side areas and side buttons, they're just made out of plain, smooth plastic.

Build Quality

Build quality is surprisingly good on the MM057, which I absolutely did not expect from such an affordable mouse. My only gripe is that it has something rattling inside, and it is definitely not the sensor lens. It's most probably internal wiring that connects the top and bottom PCBs. Apart from this small issue, the mouse is very well put together. I couldn't make it squeak or creak even when I pressed down on the shell with great force. The buttons don't seem to have any unnecessary travel either, and the mouse feet are well-aligned, too.

Weight

As for the weight, the mouse weighs about 70–71 grams without the battery. Once you put in a standard AA battery, it becomes 94 grams, which is very heavy for such a small device, and I would highly advise either using a lithium AA or lithium AAA battery, plus an adapter for the latter. With these, the mouse becomes a lot more balanced, and generally feel less sluggish in use.