I used Heyco water tight fittings on the cables. I had to desolder the ends to get the cable through the glands. I used rubber washers to seal the box where the bolts are. I used no sealant at all. I wouldn't do it like that now. I would simply use the Blue Sea split cable clams. This way you wouldn't have to do anything to the coil or headphone cables. In fact you could run both cables through one split clam.