Afam part: AS 11508-46 ....delicious little sprocky, gold anodised alloy and looks the "mutts nuts". This alloy is largely aluminium but with other "stuffs" added for superior strength. Would not last long if it was your common and garden variety window frame aluminium. I reckon it is about 9 on the bling scale and even if it was shagged in 15k it is worth it. Get a chubby every time I look at the back wheel