hydrant

So I noticed today that my yard hydrant had been leaking (thought it was shut completely off but apparently not) and the recent cold snap over the past few weeks appears to have split it near the head. Anyhow, I've watched some videos and understand the basic replacement principle of the head as...

need plunger I do not know brand but this plunger is not the big common one smaller on with smaller threads also. Anyone recognize brand.