With firefly built-in switch, current of firefly light bulb is flowing even in OFF state, depending on the type of LED lightbulb, there is a problem that it turns on even when the switch is OFF. To solve this problem, we changed to a switch that has no built in firefly. It is perfect.
It is a 4-way switch used to blink luminaires from three or more places. Use one or more 4-way switch between 3-way switch. To make it blink in 3 places, use 4 way switch, 2 from 4 places, 3 from 5 places. This switch is a type for embedding, used together with a switch box etc, and use it by embedding it in a wall or the like. It's made in Panasonic, well designed, inexpensive and likes.