Review on Adjustable DPI Wireless Ergonomic Handheld Trackball Mouse with Laser Pointer - Left and Right Handed for Laptop, Desktop, PC, Computer by Pascal Santos

I paid about $29. does what i need Nice trackball. Handy scroll wheel. Left click, right click and enter keys. I don't intend to use a laser pointer, don't see the need for two right mouse buttons, and would rather assign a Previous Slide button. However, you can use the scroll wheel to go back to previous slides, so that's not a problem for me. I find the shape handy with practice holding it still when trying to click and drag. I don't know the battery life yet. Even with a magnifying glass, I could barely read the fine print on the instructions. I liked them so much more than the wired portable mice I have that I ordered a wired one for home use. Since using this and the ergonomic keyboard, my hands seem to ache less. So, not perfect but does what I need, best of its kind I've found and costs about half of some others.