Have you already heard about this Turbo feeder?. It's not a new concept but the price is interesting. This stuff seems to be interesting for training, shadows... http://www.plusdebad.com/com/index.php/blog/nouveautes/10-presentation-du-turbo-feeder
DIY To start you off. https://www.google.com/search?q=wir...PIsjN7Aa0poCgCA&ved=0CFMQsAQ&biw=1476&bih=821
yea, it's nothing special, you can actually do it yourself, just go buy a couple feet of air hose at the diameter matching that of the shuttle, and a strap, you're done. i prefer just letting it lean on my non racket arm so i'm not wearing some bulky thing all the time.