I have a few Twosun pens and when the PEN33 in plain Titanium became available I couldn't say no to it. It has great lines and is the first one I've picked up that has the mechanism tied to the clip. Gotta say, I was a little nervous about that since I knew that the clip would stand off of the body of the pen a bit to allow the action to occur. But it goes in and out of a shirt pocket easily and holds well enough with the shirts I wear regularly. If I had to ding it for anything it would be that the flutes near the tip came with well-machined but sharp edges (I shaved off part of my fingernail when I ran it over the flutes). I have a tiny little ceramic rod that I use for deburring the detent holes in my knife blades and that took the "edge" off those sharp edges. The machining is top notch otherwise, the action is smooth with just the right amount of spring tension, and the texture on the tubes makes it easy to grip and write with. Overall, with the slightly knocked down flutes, it’s now one of my favorite Twosun pens.