Instruct: Classify an Amazon review as either positive or negative.
Query: Size is important -- Righties only

Size is important, so why doesn't Amazon provide a sizing guide... Note that large fits better if your hand is 3.5 inches across the knuckles. Otherwise get the small-medium. Also note that this item is only for right hand mousing. But it does feel good. Almost immediately. No drivers enclosed, but it is plug and play. They say that specific drivers are downloadable.