57-hole design: This may refer to the number of bubble outlets in the bubble machine, which can produce 57 bubbles per operation.
Automatic water absorption function: The bubble machine may have an automatic water absorption function, which can easily add water to create bubbles without manual operation.
Electric design: Bubble machines may be electric and need to be connected to a power source to provide power.
Lighting effects: Bubble machines may be equipped with lighting effects that can create visual effects and add fun while creating bubbles.