Serial numbers: Tour issue clubs usually have a “T” or “TC” serial number; aka: the mark of the gearhead golf nerd. (my people) No warranty: Buy a Tour-issue club and you’re on your own.

“By working closely with our global tour staff, we created Z-Star Diamond as an enhancement to our premium tour lineup [of golf balls], ” said Jeff Brunski, vice president of R&D at Srixon.

First, the similarities. They both rank inside the top-10 in club-head speed on the PGA TOUR (Rasmus, seventh, 123.77 mph and Nicolai, 10th, 123.21 mph), so they’re starting with a similar engine.