There are many styles of locks available and each provides different benefits depending on how you plan to use it. Hardened steel chains and solid D-locks with robust locking mechanisms are the safest as they take longer to break by potential thieves, making them suitable for home protection or securing the bike overnight. Cable locks are lighter and easier to carry, making them ideal for quick visits to the shop or as an anti-theft deterrent where you leave the bike for a short period.