guessing you'd be talking about the heavy pass developing balls? We've got a 'Morgan Pass Developing Ball' at my club, which I think is made by Gilbert, there are others out there too if you look for them. They're very useful for aspiring Scrum Halves - if they can get a half decent pass with one of the heavy balls, then it'll improve their long range passing with normal balls. Not the best ball to play a game of touch with, we tried it once and there were god knows how many dropped passes, knock ons and general not being able to get the ball to the next man.