Bolt VD-420 Wireless Manual Flash - Manual (Page 19)

Using the Flash | 19
To avoid overheating the VD-420 and damaging it, wait at least 10 minutes after 20 continuous flashes at full
power. The flash will automatically shut off if the internal circuit overheats. It will also alter the recycle time from
10 to 25 seconds until the flash bulb cools down.