UNYIL4D RTP SLOT In the U.S., the buttons were commonly black; the "on" button typically had a white mother-of-pearl (real or simulated) inlay to indicate its function. Pushing the raised button opens or closes the contacts and pops out the previously depressed button so the process can be reversed. The switch actuator does not control the contacts directly, but through an intermediate arrangement of springs and levers. When the mechanism passes over the center point, the spring energy is released and the spring, rather than the actuator, drives the contacts rapidly and forcibly to the closed position with an audible "snapping" sound.|The Secret History Of Slot Receh