Marin muirwoods steel disc flat bar gravel road commuting touring hybrid bike this item is in the category sporting goods\cycling\bicycles. Marin Alloy Flat Top Riser. This item can be shipped to United States. Shimano Hydraulic Disc, 160mm Rotor. These durable and smooth riding steel frames are dressed with parts picked specifically for their durability in everyday use, like hydraulic disc brakes, robust drivetrains, and tough wheels with puncture resistant tires, and the ability to add a variety of commute accessories makes sure you can customize the bike for your daily needs.