The full name for these earphones, or ear buds, is BLK : nine millimeter earphones™. Shaped to look like bullet casings, the Munitio ear buds are so macho they practically shriek "COMPENSATION!" Munitio calls them "the World's First Tactical Earphones." The tactical part stems from the "tactical finish." Ok...
I wouldn't have bothered you with these things if they weren't far better than their name implies. First off they have a decent harmonic balance without the usual and obnoxious bass boost that plagues the ranks of most mid-priced ear-buds. The midrange is relatively flat, with only a bit of excess warmth while the high end is only slightly rolled off. Compared with the Ultimate Ears Reference Monitor custom in-ear ear buds the M BLKs are more romantic but not to the point of sloppy drunk imprecision.
And then there's the fit. I have skinny little ear canals. Most ear buds fit badly, if at all. The M BLKs come with two different sized "silicone hollow point" ear tips. The smaller ones work nicely, making a good seal that stays in place even during workouts. The Munitio M BLKs are also so light and small that once properly seated in your ears they stay in place almost as securely as a triple flanged tip ear bud. And the silicon end is more comfortable than a triple flange ear tip, which needs to be inserted deeper into the ear canal.
The M BLK's cabling is strong, flexible and lightweight. It looks like it can handle the physical trauma of being used by humans well. Unlike the latest top-end Shure and Ultimate Ears ear buds, the M BLK lacks any way to remove or replace the cable if it gets damaged. But, hopefully, the ear buds will pull out of your ears before the cable gets too seriously stressed when it catches on something like a nautilus machine (which happens to me with some regularity.) My only complaint with the cable is that it's somewhat microphonic - when you rub it you can hear it, especially if the spot is near the ear buds.
Isolation from outside noise is only fair with the M BLKs - they don't attenuate the real world nearly as well as a triple flange or custom-fit earpieces. If I rode the subway every day the M BLKs wouldn't work for me. If your workout place is partial to loud "background" music the M BLKs might not be your best earphone option. But if you bike the M BLKs would be a better and safer option than a more isolating ear bud.
For $180 the Munitio M BLKs offer far more than merely macho good looks. They are light, comfortable, and don't try to pump up the bass too much. Also for folks who don't dig the bullet tie-in, the M BLKs are the least obviously shell casing-like of the Munitio line due to their dark monotone color.
If you ride a bike and use ear buds I want to especially recommend the M BLKs since you can enjoy your music and not be totally aurally isolated from the real world, which may help you stay safer longer.