Hi Bagger,
Sure, I'd be happy to.
The Boomerang works on three levels. It's a ball returner that doesn't need batteries or power, it's an addictive skill challenge and it's also a professional putting aid. Basically it keeps you coming back because it's so challenging and at the sametime it gives you excellent feedback on every putt you hit - good and bad.
But here's the thing, because the target is on a thread and can be adjusted up or down to make a lip to catch the ball, when the ball is sitting in the target it tells you about the break. If it's sitting at 6 o'clock on a clock face then there is no break, so if you hit a ball and it curves left or right there is only one other variable - your stroke. It means you are learning from good putts and bad putts at the rate of 500/hour.
But you're not just bashing away, you can adjust the height (length of putt), break and difficulty. By winding the hole down to create a lip the challenge is then to catch the first ball on the lip and then use a second ball to knock it out and return both balls to you - it is in effect a two ball putting system designed so you wont ever have to move off your spot.
If you'd like more info about the Boom or putting in general I'd be only too happy to help.
Enjoy your practice!
Cheers
Alex
PS How was that coach?