It is manufactured and released to the market under the Silver brand (and I have not seen this model under any other brands) but because of the similarity of the machines, it should be compatible with knitting machines and robbers sold under the Studio, Silver Reed, Silver and Singer brands.
I could not find a lot of straightforward information in one place. It is also impossible to find a manual. So, the information below is taken from the manual and forums and I am yet to test my AC1 color changer. The pictures below are courtesy of an eBay seller.
This AC1 color changer is very compact and all parts fit inside of a small box.
The major parts are the yarn changer itself, a connecting arm, and a needle guide.
The connecting arm shape implies that this yarn changer is compatible with the double-bed setup (main knitting machine bed + ribber). It is very likely, similar to later models, that the connecting arm can be used even without the yarn changer. So, if you have a ribber but not connecting arm, find yourself a color changer.
The needle guide replaces the one in the ribber carriage.
When not in use, it has its own place in the storage box.
The changer it self has several hooks/holders to switch and hold the yarns.
This is the information I was able to collect so far. If you have more information, write me so together we can collect as many details as possible about this accessory and to make our Knitting Machine world more complete 🙂