The commuting bike I'm intending to buy has a 7-speed cassette and double chainrings. I have a multi-tool on my shopping list, but the tool I was thinking about buying specifies it's for 8/9 speed chain.

https://www.nashbar.com/bikes/Product...4_10000_200502

(I have one of these that I carry on my Surly LHT.)

Ignorant me, I guess, but I didn't know there was a difference.

Can someone please explain about bicycle chain sizes?

What multi-tool or chain tool should I buy for a 7-speed chain?

that chain tool will work on 7 spd chain

7-speed and 8-speed chains are the same.

Actually should be just fine for 6 spd. through 9 spd. Don't know about 10 or 11.

OK, thanks. Actually I used it recently when I re-furbed my old Ross 10-speed and it worked......but that's a 40 or so year old bike, and I didn't know if anything changed since then.