its the same as the 712 irons the sole is just wider, got a good look at it in memphis, its strange seeing a mb with that wide of a sole on it.

its a 712 with a wide sole on it, got a good look at it in memphis this past week, its strange to see an mb that is as wide as it is. might be a prototype

It's not a 712 it's a 503i, made 5 or 6 years ago and never released to the public. Kyle Stanley and Gary Woodland also use them.

It is the 503 utility club. It has a tungsten weight plug in the sole of the club. I actually have a 22 degree with a s300 shaft sitting in my garage.