Sleeping Bag

[Wingfield]

Folks,

question or two for you. I have an old sleeping back that I bought circa 1989 (so between 25 and 30 years old). It's a Kelty; but there are only a few labels on it; none of which show the rating.

(a) how long does a synthetic bag last? will this bag still provide the same warmth as when I purchased it?
(b) what is the temperature rating of the bag? I have only the limited information on the labels. It shows Kelty RN70241. I've also attached 3 pictures of the tags on the bag.

thank you for any help provided.

David