DeSantis is selling a unique product called the Bag-Packer.  The system is a combination of backer board and holster that can be inserted into many different kinds of purses or messenger bags.

The board attaches to the bag, and then the holster attaches to the board.  The board has a C-clip and suspender-type clips to attach to the bag.  The holster affixes to the board using a Velcro-like material.

The system is only available in black.  Currently, the Bag-Packer system can hold a variety of handguns from the subcompact Ruger LCP to a full size Glock 17.  MSRP is $25.99.