Hello U.Hardegger, I assume that you want to use the mouse with a mac? Or is this already a new USB C power connector on a Windows computer? Unfortunately, Logitech does not yet offer a USB C-based dongle. A manual connection to the mouse is unfortunately not possible without a dongle! Therefore I recommend the following product: http://digit.ec/6069309 This should work without any problems in combination with the mouse. Greetings Andreas

In this case, we will refer you to our digitec Assistant, which provides direct contact options so that the problem can be checked and you can be helped accordingly. https://www.digitec.ch/help

I suspect that it is the same product and the price difference is only due to the different dealers. The "red" is offered by Digitec and the "red" is from a third party dealer.

The Refresh version is the V2 of the same model. The difference is in the receiver. I cannot tell you if there are other differences. http://support.logitech.com/de_ch/article/46765?product=a0qi00000069ugSAAQ