(SSMP) MONOPLUG TO MONOPLUG SAFE-SYNC Protects against high sync voltage which can cause arcing and pitting at the shutter contacts, as well as long term circuit damage. Safe-Sync reduces sync voltage to 6 volts, totally isolating the camera from harmful current levels. Does not interfere with sync circuits below 6V. With monoplug style of sync cord. Safe Syncs safely reduce any electronic flash source from up to 400 volts to less than 6 volts to the camera sync input. This is absolutely mandatory for all high end and especially all Digital Cameras.