Ernie Ball have long been renowned as the world’s most popular guitar string manufacturer. However they do tend to write rather opaque product descriptions! I have included their description of these strings below, but here is a brief synopsis from me. There are two main materials used for winding acoustic guitar strings- 80/20 bronze and phosphor bronze. Phosphor Bronze has a brighter, clearer sound but tends to rust a little faster, and 80/20 bronze is more mellow but maintains the same tone a little longer. You can find the 80/20 version of these strings here.
Here’s what Ernie Ball say:
Made from 92% copper, 7.7% tin, 0.3% phosphorus wire wrapped around tin plated hex shaped steel core wire. These guitar strings have a light orange, gold color and provide a mellow, ringing sound, with excellent clarity.