KRSEC Aluminum Bike Riser Bar Handlebar 31.8 780mm MTB AM XC DH Mountain Bike. KRSEC Aluminum MTB AM XC DH Cycling Riser Bar Handlebar 31.8 780mm Mountain Bike. Length: 780mm. It is beautiful and stylish a glance, durable and comfortable for a wide range of applications.caliber: 31.8mm / 780mm.