The thing is $159. I saw it demoed at the a recent WTA tournament. Really supposed to help train you to keep your head down and eye on point of contact. They say 10,000 strokes builds habit and muscle memory. I was really interested in getting it but didn't because it seems gimicky. May be I need to reconsider. I like that you can work on your swing indoors. For working folks who just can't always get to a court, maybe it can really keep you strokes tuned.
Anyone ever use inside?