This is a really simple power source. It will provide about 10kV at about 20 to 30 milliamperes. These are probably free or very cheap if they aren't new at a local HVAC dealer. These transformers come out of oil burner furnaces and are used to ignite the fuel electrically. They produce good arcs and are good for a Jacob's ladder or a small Tesla coil. As far as I know these type of transformers are current limited so they can be shorted with little or no risk of burning them up. You can tell if a transformer is current limited by looking to see if there are any magnetic shunts between the primary and secondary windings. Care should be used when working with this type of transformer. Although I have never heard of anyone being killed from a small neon sign or oil burner transformer, the risk of electrocution is still there so do not do anything stupid like touch the secondary (or primary for that matter) leads.