pahl, welcome to the forums!
Your Wave has liner locks for those four outer blades. This is a system where a section of the liner is split off and bent inward to slide behind the tang when the blade is opened, to keep it from closing until you want it to.
Any well-made liner lock is pretty reliable, although cheap ones can slip under pressure, especially twisting with the blade stuck in something. The big advantage is its simplicity of operation.
All the Benchmade 710 models are axis locks, in fact, the 710 was their first axis lock model. This is a cylinder that is pushed into place behind the opened blade by a spring. Pulling back on this 'axis' releases the blade to close again.
The axis is a lot of fun, and seems to be strong and reliable. SOG has the 'arc' lock and Cold Steel has the 'ultra' lock which are both very similar to the axis.
A common older lock is the lockback, where a bar of metal forming the back of the handle will press against the top of the opened tang. Pushing down on the lock will release this catch. These are solid and reliable locks.
You may also come across the term 'slip lock' which is better known as a 'slip joint' and is not a lock. In fact, it is the classic old time folding pocket knife that rotates open and closed without locking.
The integral lock of Chris Reeve Knives' Sebenza, Umfaan, and Mnandi is a naked liner lock, a liner lock without handle slabs outside the liner! Consequently, when you hold it, your hand is helping to hold that lock closed. It is the simplest, purest, strongest lock to work with.
Other companies also use this design. Tom Mayo does the renowned TNT with this lock. Darrell Ralph has designed excellent folders for his own custom work and for companies like Camillus. And even Benchmade has an integral lock model, as does CRKT. Titanium seems to be the most popular material for these handles, but steel works fine.
