How many type of lock of the outdoor knife do you know?

Outdoor knives can feature a variety of lock types to ensure safety and functionality. 
Here are some of the most common types:

Liner Lock: A thin liner inside the handle that moves sideways to lock the blade open. It’s easy to use with one hand.

Frame Lock: Similar to a liner lock, but the handle itself is used to lock the blade. It’s usually more robust and often found in heavier-duty knives.

Back Lock (Lockback): A locking mechanism on the spine of the knife handle. Pressing down on a part of the handle releases the lock.

Slip Joint: Not a true lock, but a mechanism that uses spring tension to hold the blade open. Common in traditional pocket knives.

Axis Lock: A bar that moves along a slot in the handle to lock the blade. It's known for its strength and ambidextrous operation.

Button Lock: Uses a button to lock and release the blade. Found in some automatic and manual knives.

Collar Lock: A rotating collar around the knife’s pivot that locks the blade in place when turned.

Compression Lock: Similar to a liner lock but located on the spine, providing a stronger lock and ease of use with one hand.

Tri-Ad Lock: A variation of the back lock that adds a stop pin between the blade tang and the lock bar, providing extra strength.

Lever Lock: A lever on the handle that locks the blade in place. Common in automatic and assisted-opening knives.

Ball Bearing Lock: Uses a ball bearing to lock the blade open, providing smooth operation and strong lockup.

Each type has its advantages and is suited for different tasks and user preferences.