I'm looking for the correct term for the type of holster one would use to carry a gun at one's back. I assume those people have some kind of holster and not just the gun tucked into their waistbands, do they? Like in crime shows when people reach behind themselves and pull out the gun. How would you call that kind of a holster? I've googled "holster back", "holster worn at back" and similar but am not finding any satisfying results. I'm basically looking for a place where someone would carry a gun when they walk around with it all day. So it should be fairly comfortable and not too obvious. Any suggestions (with proper terms) would be most welcome!