Compact and cate --- 8 joints foldable bike lock with dimension of 12*6*4 cm / 4.72*2.36*1.57 inch(L*W*H) and weight of 28.2oz/0.80kg. The small shape make it not only easy to be stored in backpack or bike bags, but also can be attached on bike seat tube. It fit for many different bikes such as mountain bikes, road bikes and commuting E bikes.Strong and Durable Material --- The folding lock is made of steel alloy. Each piece with thickness of 0.39inch, making it strong, durable and unbreakable, bolt cutter drill and saw proof. The black rubber coating outside the steel is soft and water resistant, not only help to keep it from scratching bike painting, but also protect the inside metal from corroding after years of use.Long Chaind Reliable Protection --- flexible foldable lock opens to 35inch / 90cm chain link circumference, can lock bikes to most nearby poles, trees, or other stands racks and bars easily. It also could lock 2 bikes together, provide protection for both when you do outdoor exercise with friends.Safe and Simple Installation --- There are 3 keys attached in the folding lock, support to keep 1 in key chain, 1 in backpack and 1 for backup, no worry about keys missing. Before each riding, simply clip the folded lock on the mount bracket and it will stay out of the way until you need it. The adjustable diameter of the mount suitable for any size of seat tube.Reflective Sticker --- The mounting come with a reflective sticker, which can help to alert other bikes or cars behind to avoid, provide night commuter and cyclists a safe night riding. Even when park bike on roadside, the reflective sticker still works to remind walkers in the dark.