OnGuard 8590 Rock SolidSmart Security U Lock for E Bikes and Cargo Bikes Introducing the OnGuard RockSolid, a toptier Dlock engineered for riders who refuse to compromise on security. Built using a proprietary blend of ultra highstrength materials and a multilayered defence system, this lock is purposedesigned to resist the most destructive tool in a thiefs arsenal, the angle grinder. Its hardened, shrouded shackle and antigrinder patented material make it virtually