A pastry cloth pad is used to hold a pastry cloth in place on a worksurface to stop it from sliding as pressure is being applied to the dough on it.
It is typically a large pad usually made of rubber.
You place it on the counter, and place your pastry cloth on top of it, and then for the full outfitting, a rolling pin cover over top the rolling pin.
The pads, generally around 60 by 50 cm (24 by 20 inches), help to hold the pastry cloth in place.