These are Megalodon Display Plaque - Display Nameplates
They will fit on any square M/L/XL/XXL wood stand base sold by Dark Water Megs and a variety of others, they can lean against posts or be attached via an included adhesive strip.
Please watch the video to see the very simple installation and removal of the protective film.

Please note, these are $9, they are for the metal display plaque, they do NOT include the stands, teeth, uprights, bases, etc pictured above.