Use a tiger to guard your bike. A lightweight titanium TiGr lock, that is.
Quite possibly the most important bike accessory you can own is a lock, and the TiGr models are unique and lightweight alternatives to U-locks.
When it comes to the stuff you carry with you when riding your bike, there are a few crucial pieces, with a flat kit and water bottle ranking pretty high on the list, but a lock for your trusty two-wheeled steed is pretty crucial as well. If you're just going on a ride, with no intention of making stops along the way, then by all means leave the lock at home, but if you love your bicycle (and who doesn't?), and you need to park your bike unattended for a while, then a bike lock is a must-have. And not just any lock will do, as bike thieves can quickly relieve you of your ride if you rely on a cheapo lock or cable. U-locks can be a good choice, but they're also heavy to carry along, which is why the TiGr Lock models are a good alternative.
Initially launched by Stanton Concepts via a successful Kickstarter campaign back in 2011, TiGr locks have proven to be a great option for bicycle security that not only look good, but also weigh in at a fraction of a standard U-lock, while standing up to a variety of lock-breaking methods. There are two basic versions of the company's bike locks, both of which employ a deceptively thin band of titanium to secure the bike, and a "highly pick-resistant" lock made from 304 stainless steel, and which have been subjected to rigorous attack testing, and have passed with flying colors.
"TiGr® Locks are very secure. All TiGr® Locks have been certified to meet rigorous European bicycle security standards. The TiGr® mini can secure the frame and a wheel to a bike rack. Bow-Locks can capture more of the bike, or more bikes. Standard and Long bows can capture both wheels without having to remove a wheel." - TiGr
The original TiGr Bow-Locks, which come in three lengths (for securing a single wheel and the frame, both wheels and the frame, or multiple bikes), have a 1.25" wide titanium band that can be attached to the frame when not in use, and weigh in at either 1.3 lb, 1.7 lb, or 2 lb, depending on the model. The titanium band has a PVC coating on it to protect your bike's frame, and prices on the Bow-Locks range from $159 to $199, complete with a full lifetime warranty.
The TiGr Mini is a smaller version, measuring just 7" long and weighing in at less than a pound, but features the same 1.25" titanium band and secure locking mechanism, and can be carried onto the frame with a bracket that fits the standard frame lugs used for water bottle cages, pumps, etc.. The TiGr Mini costs $99, and comes with the same warranty as its big brothers.
More info is available at the TiGr Lock website.