She's a little beat up but sounds good and has mojo. The Harmony H303 is a small three tube combo amp from the early '60s. It has a Jensen alnico 6" speaker and an isolation transformer for safety from the AC power side. This all octal tube lineup includes the preamp tube which is a metal shell 12SQ7 single triode, the power tube is the 50L6 pentode and a 35Z5 tube.
Please note I'm not an electrician but it has a two prong plug. Therefore, I recommend any buyer put in a three prong grounded plug. It has an isolation transformer according to the parts list which makes it much safer than those without.
It might be prudent to consult a knowledgeable electronics person to ensure you have taken adequate steps to ensure it is safe as I said I'm not an electrician.
When you call please mention you found this ad listing on OKz.ca