Most Pastry Jiggers made now are wheels with ridges in them, designed to put a “jiggedy” or wavy edge on pastry, while cutting it out as well.
The term “Pastry Jigger” is often used interchangeably with “pastry wheel”, because some models will cut out pastry as well. Pastry wheels can be designed to both cut out pastry, and decorate the edge.
But there have been in the past Pastry Jiggers made that weren’t designed to cut pastry, just mark it.
Some antique ones had a handle, then the end having 3 different branches on it – one holding a square marker, one a circular marker, and one a wavy edge.
Some had a ridged wheel on one end, and a spoon on the other end, to make them dual purpose tools. Early American ones might have the wheel carved of wood.
Antique ones are now collectibles.
Substitutes
Crimp the edges of a pastry by pinching it with your fingers; or use the tines of a fork.