Note: This information was taken from TSR's original AD&D adventure, the Temple of Elemental Evil.
LEOMUND'S LABILE LOCKER

This copper-bound box is two feet wide and tall, and three feet long. Invisible runes are scribed upon its front; these reveal four command words. The first shrinks the box to a twelfth of normal size, with all contents likewise becoming minute. The weight of the shrunken chest, empty or filled, is 30 pounds. The second word causes the chest (if of normal size) to function as one upon which a Leomund's secret chest spell has been placed (but with no smaller replica necessary!). The third word causes the box to return to full size or normal place, as applicable. The fourth word causes growth to quadruple dimensions, with sides, top, and bottom of one foot thickness, huge copper bands, and a weight of 1,200 pounds.