Here is the Merkur 39C next to the Merkur 23C. The 23C is a double-edged razor that's ideal for beginners, with a nice long handle, mild shave and (relatively) light weight. By comparison, the 39C has a seriously hefty handle and slanted bar with a much wider blade gap. If the 23C feels about the same weight as a fork or spoon, the 39C is like a solid-handled butter knife (although more balanced).
Here's another look at the Merkur 39C slant. Just look at that handle. The barber pole style knurling is deeper than it looks and gives a very tactile grip. The heavy weight coupled with the more efficient slicing effect of the slant bar means you really can let the razor do the work. It's also the reason this razor is known as "the sledgehammer."
Here's a better image of the blade... and part of my fingerprint on the mirror chrome finish. Like all double edge razors the cap that sits on top the blade bends it into a crescent, but in this case the entire safety bar has a twist. The gap between the safety bar and the blade is huge compared to the 23C. The bar also has a toothed design and the cap has a series of indentations making a wavy shape as well. These features give a very close shave and also mean that lather and whiskers are kept away from the blade for longer, so you can take longer shaving passes before cleaning off your razor, if you choose. Basically there is more space for the lather to flow away from the blade.
Above is a look at the Merkur 39C razor disassembled. The long threaded rod on the cap goes through the blade, which is held relatively square by the lugs on the bottom of the cap. The knob at the end of the handle has a female-threaded hole and is held in place by a simple spring retaining ring. To tighten the cap or remove the blade you just unscrew the knob and the cap comes off, you do not have to remove the knob.
Another look at the cap. The edge of it is really quite thin. You can just make out the forge marks. The underside is still chrome plated, just not mirror polished.
Here's one way to load the blade into a Merkur 39C. This is how Merkur recommends blades be loaded. Place the cap flat side down on your counter, drop a fresh blade over the lugs and center rod, and screw the handle on. This usually works okay, but I've found sometimes the blade is slightly out of alignment, with more of the blade exposed on one side of the head than the other.
Here's another method for loading the blade into the 39C that I've found works better. If you pick up the cap and squeeze the ends of the blade lightly while pushing up on the cap, you cause the blade to flex upward and form to the shape of the cap. From here it's easy to screw in the handle and ensure the blade is evenly exposed on both sides of the head.
Another look at the fit and finish when disassembled. You can see that the safety bar and handle are actually two pieces with a joint where they meet. While you could probably make a much more appealing version by machining the whole thing out of stainless, this is probably a lot more cost effective.
A look at one side of the head. You can barely see the blade arched up under the cap. Because this twisted head is obviously asymmetrical, at first glance you might think it's defective. But it's actually supposed to be like that.
Okay, enough with the eye candy. You're probably wondering how this bad boy shaves. The answer is that it's the best shave I've ever had. I found that I didn't need to make any adjustments to my technique to avoid cutting myself, and frankly everyone had me scared with the whole "not for beginners" thing. The honest answer is that this tool is no more dangerous than any other razor if you have good technique. While it excels at busting through multiple days of growth, it also lets you get a ridiculously close shave with minimal irritation. The twisted head naturally forces more of the blade to contact each whisker, slicing through it more efficiently than if it had contacted the hair straight on. Or if you've heard of or tried the "Gillette Slide" technique, where you use an ordinary double edge razor and shave in a diagonal line across your face while keeping the handle straight up and down, the effect is the same.
The bottom line is: if you want the last razor you'll ever need, with a close, comfortable shave that's aggressive enough to take down two or three days worth of growth in a single pass, the Merkur 39C slant bar is the razor for you. Plus, there's a serious macho factor involved. You can tell everyone you shave with a sledgehammer. What's cooler than that?