I use some older flashes that have a lot higher trigger voltages and may damage my newer cameras if used in the hot shoe mount. Therefore as a precaution I use the PC sync with them instead and mount them on a cold shoe adapter that rests in the hot shoe of my camera. By doing this there is no potential high voltage connection between my camera and flash.
Are there any accessories (possibly using a surge protector) that I can put in my hot shoe and let me use the old flash guns protecting my camera from possible harm?