Learn to grind at home! The Madd Gear grind rail is a great mobile option for bringing the skate park to your house! The Madd Gear grind rail is adjustable, starting low and allowing kids to learn to grind and improving their skills before taking it to the skatepark on larger obstacles. Easy to assemble and compact - the Madd Gear grind rail is ideal for use in the driveway and when friends come over! Coming in at 55" long, this grind rail is ideal for beginners and advanced riders alike. Complete Assembled length is 55 inches long, and has a three step adjustable height up to 8.5 inches. The diameter of the rail is 2.5 inches.