hoosier:O-ring is an ordinary size and shape that we can get from the hardware store?
It's a thin Teflon coated o-ring - unfortunately, impossible to find where I am; I have to get it from the UWATEC battery kit (06.201.919 - the part number for the o-ring only is PN 06.201.610). I have no idea whether you would be able to find it in a hardware store in the US.