The ravensburger puzzle sorting trayss are 6 stackable trays for sorting and storing your puzzle pieces big enough to hold all the pieces from a 1000 piece puzzle the blue puzzle shaped trays can be linked or stacked whichever you prefer each tray measures approximately 19 x 19 x 2cm and is made from high quality plastic the trays stack within the box supplied so you can store your puzzle pieces away like this if you prefer these trays will last for years so forget about using margarin