SmartCarry has been in business since 1990 and is 100% made in the USA. The SmartCarry holster is a denim pouch that is worn inside the pants, supported by an velcro elastic band that goes around the waist. It's kind of like wearing a cup. Wearing it takes a lot of getting used to, but like any other holster, after a while you forget its there. The side facing the body is made of sweat-resistant Cushmax, and it seems to work well.
There are a variety of custom configurations available. I shoot left handed, so mine is set up this way: The left side of the pouch has a large pocket for the pistol (Glock 19). The barrel and trigger are completely covered, and the grip is completely exposed. The right side has a smaller pocket for an extra mag or flashlight. There is a flat, full-width pocket in the back for money, ID, permits, etc.
The strap is worn low on the body. It must be worn below the hips, so that the entire assembly is hidden inside the pants. The barrel of the gun should be aligned with the centerline of your body. If you lift up my shirt, you won't see anything (besides my big fat belly). It works equally well for males and females (I'm told) in any type of clothing. I have worn this with all types of pants including jeans, shorts, sweatpants, gym shorts, dress pants, pajamas, and uniform pants. It can be worn with or without a belt, because the holster has its own waistband. With a little bit of adjusting in the mirror before I walk out the door, nobody can tell that I'm carrying. Sometimes in a seated position, the barrel of the gun can make it look like I've got a boner, but it is easy enough to shift into a position which accommodates this.
The SmartCarry allows pretty decent mobility - I was surprised. I've been able to do any of my normal exercises without any difficulty. It's great for deep concealment. The biggest drawback is that it takes longer to draw. Of course this gets faster with practice, but for now I'm pretty slow. I like to keep my belt snug, and if my belt is snug then I have to wriggle my hand down in, and then out, with a gun. So I have had to keep my belt a little looser when wearing the SmartCarry.
BOTTOM LINE: SmartCarry is exactly what I was looking for to carry in the gym. I occasionally also use it for deep concealment inside my uniform. The rest of the time, I prefer to stick with my BladeTech IWB holster, simply for speed of draw. HOWEVER, I still wear the SmartCarry even when I'm carrying IWB, so I can conceal an extra magazine, light, etc. on my person!!
Disclosure: Other that owning one SmartCarry holster, I am not affiliated with them in any way. I am not being compensated for this review. This is purely for your information.
I'd be happy to answer anyone's questions.