For starters, supposedly, Amazon bought Logitech's design for their top of the line Performance MX which has been discontinued, so now Amazon has the rights, and they've produced this cheaper version of it. Trust me, it's NOT the same. It's smaller, which makes a big difference when you go to pick it up because it slips out of your hand. And just the feel of it overall does not compare with the Performance MX. So either Amazon changed the design after they bought it, or Logitech didn't sell them the actual design of their top rated mouse. The weight is lighter also, which is a negative. The Performance MX was the perfect weight. As for the instructions, I don't know what the writer was on, but oh my goodness. The booklet tells you to remove the battery cover (without any info on how to do that), insert the batteries, and then put the cover back on. The very next step is to remove the battery cover. Unbelievable but true. Remove the battery cover and take out the nano receiver that is tucked inside the battery compartment. Okay. So I looked and looked, but the place where the nano receiver was supposed to reside was empty. So, as I started to pack it back up and send it back, lo and behold, there was a little cardboard box, with the perfect size shape for the nano receiver. And there it was. Fitting perfectly in it's little hiding spot. I say, hiding spot, because the box looked just like packaging material and it could have been easily missed and thrown away. Amazon must be hard up for good technical writers because it's not like them to make things 10 times as hard as they need to be. Just a warning. Don't follow the instructions. You're better off thinking it through on your own. Other than all that, the mouse works, but don't expect it to feel like your Logitech Performance MX. ans it doesn't fit your hand as well, so when you pick it up, it slips out of your hand.