DANFOSS / EATON-RET RG

Correct, this is a spare part retaining ring, sold individually.

Multiple sizes are available for this part, so you're not locked into a single option. The SKU 16075-300 covers the Danfoss / Eaton retaining ring line, and sizing variety is built into what's offered. If you know the specific size you need for your application, that's the detail to have ready when you order.