This is an older generation Duosida charger adapter (~3.86 kW).
Outlet Compatible NEMA L6-20: in addition to a NEMA 5-15 and a 14-50 Plug Adapter set.
It has 3 different output settings 8A (110v), 12A (110v), 16A (240v). Setting changeable by shaking the unit (weird, but it is what it is).
Asking price: $175
Location: SF bay area (San Jose CA)
