Retaining ring for enlarger lens

Excuse my ignorance, but I just purchased a Nikkor 50/2.8 lens for my enlarger and noticed that some stores sell retainer rings for the lens. I bought it on Ebay, so I have not received it yet and I do not know if it has the ring. Is the ring necessary? With my present Omega cheapo lens, it just threads right into the metal mount on the enlarger (C700) with no ring needed. Thanks.

Jmal

If you have a threaded mount then no need for a ring. Most of my lenses are 39mm and thread right into the enlarger.

Thanks, Nick. That's good to know. I couldn't see any reason for one, but you never know.

Jmal