It is a large round plate, similar to a pan lid, with a knob in the center to hold onto as you flip the tortilla. When finished cooking, some flippers can be used to serve the tortilla, the knob acting as a pedestal.
Exactly how do they work? The idea is that after you have cooked one side of the egg-potato mixture in a frying pan, you slide it from the pan onto the flipper, which is cool and lighter weight. Then, flip the tortilla back into the pan to finish cooking the other side.
Because the typical size for a tortilla is between 8 and 10 inches in diameter, the weight of the frying pan and tortilla mixture isn’t too heavy, but it can still slip around, so it's safer to flip the tortilla over the sink for good measure – whether you use a large dinner plate or a giratortillas.
Giratortillasare available on the web from several retailers in the US and UK. Plastic versions of giratortillas can cost as little as US$5-6, but it's easy to spend upwards of US$30 for a colorful, hand-painted ceramic one. This kitchen accessory seems to be popular with expats living in Spain, but it's not clear how popular they are with Spanish cooks, who’ve grown up flipping tortillas with plates.
Below are links to two examples of giratortillas available from retailers in the USA: