Alf J Parker Twin Zero 4/80 sight

[Alan de Enfield]

The AJ Parker identification system for their TZ sight was made up of the rifle model followed by the year of design.

The 4/47 (No 4 rifle sight designed in 1947) was replaced by a later model 4/80 (for the No4 rifle designed in 1980)

Another example : The TZ 14/35 (for the P14 designed in 1935) was replaced by the TZ 3/57 (for the No3 rifle and designed in 1957)