Made in the USA from 6061-T6 aluminum alloy, Cosine Chainrings are round and true They fit 104 BCD four-bolt cranks and are available in black anodized with laser-etched graphics from 38 to 45-teeth 104mm 4-bolt 42T 6061AL 11749 Black 1sp StandardUPC/EAN/GTIN: 639266089872