Abus' Amparo 495 Frame Lock bolts to your bicycle to offer convenient security for your bike. When locked, its 8.5mm-diameter steel shackle passes through the rear wheel so your bike can't be ridden away. The Frame Lock is always there when you need it and it's built tough of hardened steel. This lock locks the rear wheel. Be sure to get and carry a second lock (sold separately) made to lock your bicycle to an immoveable object.