Deadbolt...    A deadbolt or deadlock, is a locking mechanism distinct from a spring-bolt lock because a deadbolt cannot be moved to the open position except by rotating the lock cylinder. The more common spring-bolt lock uses a spring to hold the bolt in place, allowing retraction by applying force to the bolt itself. A deadbolt can therefore make a door more resistant to entry without the correct key.

A deadbolt is often used to complement a spring-bolt lock on an entry door to a building

Cylinder Lock....   A cylinder lock is a lock in constructed with a cylinder that a locksmith can easily unscrew to facilitate re keying. The cylinder may contain any of a variety of locking mechanisms, including the pin tumbler lock, the wafer tumbler lock and the disc tumbler lock.

The first main advantage to a cylinder lock is that the cylinder may be changed without altering the bolt work. Removing the cylinder typically requires only loosening a set screw, then unscrewing the cylinder from the bolt work. The second is that it is usually possible to obtain, from a lock manufacturer, cylinders in different formats that can all be used with the same type of key. This allows the user to have keyed-alike, and master-keyed systems that incorporate a wide variety of different types of lock, such as night latches, deadbolts and roller door locks. Typically, padlocks can also be included, although these rarely have removable cylinders.

Standardized types of cylinder include key-in-knob set cylinders, rim (also known as night latch) cylinders, Ingersoll format cylinders, American, and Scandinavian round mortise cylinders, and Scandinavian oval cylinders. There are also standardized cross-sectional profiles for lock cylinders that may vary in length - for example to suit different door thicknesses. These profiles include the euro profile (or DIN standard), the British oval profile and the Swiss profile.

Cruciform pin-tumbler locks may also use interchangeable cylinders, as do a few sophisticated lever locks.

Individually Keyed System (KD)
With an individually keyed system, each cylinder can be opened by its individual key.

Keyed Alike (KA)
This system allows for a number of cylinders to be operated by the same key. It is ideally suited to residential applications such as front and back doors.

Master Keyed (MK)
A master-keyed system involves each lock having its own individual key which will not operate any other lock in the system, but where all locks can be operated by a single master-key.

Grand Master Keyed (GMK)
This is an extension of the master-keyed system where each lock has its own individual key and the locks are divided into 2 or more groups. Each lock group is operated by a master-key and the entire system is operated by one grand master-key.

Common Entrance Suite / Maison Keying (CES)
This system is widely used in apartments, office blocks and hotels. Each apartment (for example) has its own individual key which will not open the doors to any other apartments, but will open common entrance doors and communal service areas

Bicycle lock... A bicycle lock is a physical security device used on a bicycle to prevent theft. It is generally used to fasten the bicycle to a bicycle stand or other immovable object.

An important difficulty in preventing the theft of a bicycle is that the wheels are easily detachable from the frame, and that unless both wheels and frame are secured, the parts not locked can easily be carried away after being detached. The most secure locking method therefore is to lock the wheels and frame to each other and to an immovable object.

Locking devices vary in size and security; the most secure tending to be the largest, heaviest and least portable. Lesser equipment is used to deter attempts by less skilled and determined thieves. Thus like other security equipment, bicycle locks must compromise between security, portability and cost. Some are made of particularly expensive materials chosen for their acceptable strength and low density.

A flat, non ferrous metal, shaped double acting movable ‘detainer’ in a lock. Usually pivoted, but sometimes slide. The levers in a lock have to be moved by the key to operate the lock. The belly of the lever is cut away to various depths to provide different combinations. A lever will have pockets and gates through which the bolt stump moves during unlocking.

The Abloy Disk lock or Disc tumbler lock is a lock composed of slotted rotating detainer discs. A specially cut key rotates these discs like the tumblers of a safe to align the slots, allowing the sidebar to drop into the slots, thus opening the lock. Unlike a wafer tumbler lock or a pin tumbler lock, this mechanism does not use springs. From a security standpoint, the disc tumbler lock cannot be bumped. The lock was invented by Emil Henriksson in 1907 and manufactured by Abloy. Another popular brand in Malaysia is Solex.

The lock is difficult to pick and is sold as a "high security" lock. Picking the lock requires a lot of time, a dedicated, professionally made tool and special expertise, but has been done. The locking mechanism can be also disabled destructively by drilling into the lock to destroy the sidebar. Anti-drilling plates can be installed to prevent this.

In areas of the world where this type of lock has historically been rare or unknown, the term disc tumbler lock is sometimes used to refer to wafer tumbler locks.