Though a standard heavy frontwire diameter, the base of this hook hides a large bore plug-in backplate reminiscent of a thumbtack.  The oversize rear rim catches and grips the back a vertical display upright once inserted in the mounting hole.  The design raised doubts in my mind, but was actually very stable and gripped very well in use.

Step through the entire series by following…
Large Bore Plug-in Hook #1
Large Bore Plug-in Hook #2
Large Bore Plug-in Hook #3

For Plug-in Fixtures by Title
Plug ‘N Play Jewelry Display
Wood Inlay as Point-of-Purchase Display
Basketball as a Seasonal Theme
Bar Merchandiser Plugs-In
Large-Bore Plug-in Hook
Tree-Like Display Sports Metal Faceouts
Hat Ledge Plugs In
When to Use a Permanent Hook
Baseline Post for Plug-in Hooks
Plug-in and Pegboard Hooks Combine
Plug-in Hook of a Different Sort
Plug-in Digital Signage

For ongoing research of Plug-in resources follow…
Plug-in Tag” for scrollable list of posts on FixturesCloseUp
Plug-in Hooks Pinterest Board” for visual summary
Plug-in Hooks Index Page” for all resources combined

For related Bayonet-Mount Fixtures by Title
Bayonet-Mount Outfits Acrylic
Bar Outfitted with Bayonet Mount
Bayonet-Mount Hook
Hidden Hex-Key Mount Faceout

For ongoing research of Bayonet-Mount resources follow…
Bayonet-Mount Tag” for scrollable list of posts on FixturesCloseUp
Bayonet-Mount Hooks Pinterest Board” for visual summary
Bayonet-Mount Fixtures Index Page” for all resources combined