With the US Open just days away, players have been familiarising themselves with the Erin Hills course and the big talking point is the rough.
Kevin Na posted a video on Instagram demonstrating how penal the deep fescue rough is.
He tossed a ball just a few yards off the fairway and watched it disappear to the bottom of the knee high rough. Then he tried to hit the ball out of the rough, failing to make contact the first time and then when he did move the ball it vanished and could not be found.
"Every hole we've got this," a slightly agitated Na said.
Watch Na’s experiment here.
While England’s Lee Westwood and his caddie, Billy Foster, poked a bit of fun at the penal rough.