Hello, I need to buy some long distance wireless mice to run the laptops in my Science department. The teachers need to be able to stand at the side of the lab and than operate the mouse to control the laptop/projector combo. As it is a school the price is important and I haven't got loads of money left to spend. I have bought the little Microsoft optical 4000 but it loses the signal after no more than 2.0 metres. So this is fine close to the computer but we need to be able to pass the mouse round the lab for pupils to use from their seats without having to move. Your advice please on what to buy bearing in mind my funding issues. Cheers, PeterT.