Ever since I first saw the unusual design of CRKT's M21 and M16 series, I've felt very drawn to it. Carson definitely hit a home run when he came up with the concept for that specific platform! Though I have several iterations in my collection, the two shown in this photo are my favorites. The larger knife is the M21-04 and the smaller one shown in the foreground is the M21-02. Both have titanium handles...and the finish on the scales is nicely "grippy". Both are designed with a flipper deployment...though you could use the thumbstuds in a pinch. The thumbstuds are really more useful in the open position as a type of blade reinforcement. Both knives feature the AutoLawk device...and it works very well. I'm also extremely fond the blade shape. Of the M21 and M16 designs, these are top-of-the-line CRKTs. While the blade steel is Aus8A...they would benefit from better choices of steel material (154CM?). I would also like to see CRKT increase the thickness of the liner-lock. All in all, this is a great knife design and these two blades make great EDC companions!