Complete with side bearing & lamp bracket. Needs post top SC0020 if used as a straight post signal; use in pairs for bracket signal base posts. Almost always found with upper quadrant arms from the S0012 series, but a very few had lower quadrant arms (S0011).
As you can see, these posts are often twisted as they come out of the mould. Straighten them by pushing a suitable former (e.g. screwdriver, wooden strip) into the centre gaps.