This is a D.M. Bullard Dual Carry for a Glock 19 which sells for $100 plus shipping. I believe it will also fit Glock 23 and 32's as well. It also works good with a Glock 17 size pistol. The blue gun in the photo is a Gen 4 17.
The D.M. Bullard site (www.dmbullardleather.com) describes this holster as:
My #1 Selling IWB Holster
Dual Carry is the most versatile holster I make the Belt Clips can also be moved to the Tuckable position hardware is provided. All Dual Carry holsters will have reinforced opening. This holster is made to be worn at the 4:00-5:00 position behind the hip and Will Not Carry for SOB (small of back) or Crossdraw.
This holster is a IWB and OWB just remove the screws and the belt clips move from the front to the back made for most autos and revolvers.
I may have worn this a couple times over the years. I'm selling because I've sold my Glock 19 and want to empty the holster drawer.