Due to extreme market fluctuations and NOT being a "silver dealer" that makes a commission on sales regardless of price going up or down, Silver electrodes are necessarily expensive in order to avoid bankruptcy should the price suddenly double between bulk purchases...as it HAS several times over the years.
You may be able to find a better deal on raw wire and make your own electrodes.
"Series" pertains to electrode type as the sockets and configuration has changed over the years.
Re-useable Electrode Diameter Adapter for Series 2 Generators
The purpose of the diameter adapter is to make 12 gauge wire fit the [Series 2] electrode sockets.
If #12 wire is used un-adapted, bending it while in the socket may destroy the springs inside.
To use: Insert the brass adapter into the socket first, then slide the wire electrode through the adapter till the spring tension inside holds it in place.
10 gauge wire [#10] can be used to make your own [Series 2] electrodes, but is sometimes a little too big around.
The end that inserts onto the socket can generally be scraped down with a sharp knife till it fits.
Electrodes should be 7” long, total.
They don’t have to be U shaped but will last a lot longer if they are.
To help prevent tip discharge erosion from making “needles” out of straight electrodes, bend the tips slightly away from each other.
If the tips aren't in the water, they can't concentrate current/ion discharge at that location.
The Current [ Series 3 ] "Silver 9" uses unadapted 12 gauge wire, only. [No adapter needed...#10 wire will not work]
Other than that, the electrodes are the same as for Series 2 generators.