Sun Race Sturmey Archer have modified the design and manufacture in many respects; compared to the old AW hub, the current three-speed equivalent (SRF3) now has an aluminium alloy shell for lighter weight.
According to Schraner and Brandt, an aluminium alloy shell reduced spoke breakage due to aluminium being softer allowing the spoke to seat into the flange and disperse the stress at the bend in the spoke over a wider area. the top gear is direct drive and the others are geared down from it) and the internals are based on the newest five-speed freewheel hub (in the same way as the original fixed ASC was based on the contemporary FC four-speed hub).
This hub date marking will show the last two figures of the year and the month.
From 1932 to 1939 Sturmey Archer used the model designation with just the last digit of the year. I have seen hubs with the letter A which I believe are 1930 but as yet I have not been able to confirm this.
This is different from a modern standard bicycle dynamo, though replacements can still be had.
The Dynohub was Sturmey-Archer's hub dynamo for bicycles.
The GH6 version produced a rated output of 6 V, 0.33 A (2 W) from a 20-pole ring magnet with a stator having a continuous winding.
Original headlamp bulbs are 6 V, 0.25 A (1.5 W) (e.g., CRY5) and a rear bulb of 6 V 0.04A (0.24W) (e.g., CRY8).
The name dynamo implies DC output, but as usual with bicycle dynamos (known as generators in North America), output was in fact alternating current.
Dynohubs were offered as front hubs and as rear geared hubs.
If you have a hub which contradicts any information on this page I would like to hear from you.