Suitable for standard 8.4" / 7.5" /7" brake calipers. Also used for front wheel cylinders on twin leading shoe type drum brake cars.
This is where you have 2 cylinders per hub as opposed to the early single leading type which had one cylinder only per hub. Not suitable for Metro 4-pot calipers which use metric nipples (see BAU1790).
Also used for slave cylinders.