As seen here;
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F202222736561
If it's the replace the outer drive pulley, now that'd be nice.
The photos show 3 boxes, but only two pulleys. As far as I recall, you just get the two driven pulleys.