Mizuno plans to introduce a successor to the MP-600 driver with its sliding, variable back weight system in the next couple of months.
The new Mizuno MP-630 driver with red, black and silver livery, is currently being tested by Mizuno's No.1 staff player Luke Donald at the Bears Club in Florida, along with MP-630 fairway metals and a new hybrid.
Donald revealed in his diary that he's trying to get 'dialled in' to the new driver 'but with 45 different weight settings, I’ll need some help!'
Two weights in the back of the sole can each be slid into nine different positions offering golfers a combination of 45 different options from heel to toe to change flight and trajectory.
The clubs are due to be officially unveiled at the PGA Merchandise Show in Orlando and released for sale in February.
Donald, who is splitting from his caddie brother Christian, is also testing a new set of Mizuno MP-68 irons.