You can use an action to roll the box up to 15 feet away, and a bonus action to step on the switch, causing the top of the box to pop open. The box stays open so long as pressure is maintained on the switch. While the box is open, a 15 ft cone of effect originates from inside the box, pointing straight up.
The Box of Incorporal Imprisonment only affects large or smaller incorporeal creatures with 20 or fewer HP. Any such creature in the area of effect must succeed on a DC 13 DEX saving throw or be pulled instantly into the box. Such a creature restrained by two or more Confinement Streams automatically fails the save.
A small corundum jewel on the front of the box will glow red if the box is holding a creature, or green if it is empty.
The inside of the box is a pocket dimension large enough to hold 1 large, 3 medium, 5 small or 10 tiny incorporeal creatures. Once the box is closed, it cannot be opened from the inside. Trapped creatures can only leave the pocket dimension if the box is reopened for more than 6 seconds.
Opening a Box of Incorporeal Imprisonment inside an extradimensional space created by a bag of holding, handy haversack, or similar item instantly destroys both items and opens a gate to the Astral Plane. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through it and deposited in a random location on the Astral Plane. The gate then closes. The gate is one-way only and can’t be reopened.