Post War Ajack 4 x 90. Manufactured between 1954 and 1964 by Alfred jackenroll and Co. The 4 x 90 relates to the magnification x luminosity. This was a commercial hunting type scope with internal windage and elevation adjustment whereas the pre war 4 x 90 had only internal elevation adjustment with windage being catered for in the mount base.

Cheers,

Simon.