Fender Musicmaster or Duo Sonic pickup that would be correct in a guitar from 1959 through about 1964. These work great in Strats!
The only real difference between these and Strat pickups is that these have flat pole pieces that are flush with the top bobbin plate. This one was wired on a Strat pickguard when I received it, in the neck position and the wire leads were long enough to reach the controls. Measures 5.28k.