P4 Super Slim 21 grams Rough Grip, 90% Tungsten, Extremely Slim Barrels They are so slim that you can fit 21 of them in a triple segment on the board. They are only 15/64nd of an inch in diameter. The darts are manufactured from premium 90% Tungsten alloy. The knurling (rough) will help you to hold the dart and prevent it from slipping as it is released from the fingers. The medium knurling will help to stop the dart from slipping as it is released from the fingers. The darts are packaged in hard dart case with 2 sets of M4 Slim shafts, and two sets Ex-Tough flights. These are the slimmest darts in the world. These darts use M4 Super Slim Shafts.