Any ideas on where to buy this seemingly unattainable part? online chat with Sena, support person told me that upper management doesn't allow them to sell them alone and I must replace the whole unit. called 1-800 support, he sent an email, if I provide purchase receipt and photos of serial number they will send a replacement. I want to simply BUY the rubber port cover, I bought the SMH used, so Ill try sending photos, but I doubt they will help me. there has to be some rubber cover from China that can be made to work? had I know it was missing the port cover I would not have purchased the unit.