Litelok claims to have made the world's lightest and toughest angle-grinder resistant locks - BikeRadar
SeatyLock Hybrid Saddle Bike Lock - Multi Patent 2 in 1 Locking Bike Seat - Innovative Lightweight Anti Theft Bike Lock and Saddle with Keys : Amazon.co.uk: DIY & Tools
RK Bicycle Lock | MR.DIY
How to lock your bike (properly) | The Best Bike Lock
DIY GPS tracker helps you locate your stolen bike | Arduino Blog
DIY Bicycle Lock - YouTube
Choosing Bike Locks: Small, Medium or Ridiculous? – Tales On Two Wheels