Chain links or pins

[ParaBag]

Hi all - sorry, this is probably a really obvious answer, but I am feeling a tad thick today!

My bike has a KMC Z Narrow chain, and I was considering getting a couple of links in case of breakage...however I noticed a colleague carries chain pins rather than links as that is what his LBS recommended (although he has a shimano chain). What is the best thing to carry - ie, I am popping to halfords later and might pick something up.

I have a seven speed I think (7x3......or does that make it 21??), although the front derailleur says 8 speed?

Every so often, the chain has some alternative numbers on the links, of "2L" and "5" if that makes sense to anyone??


I have seen these.....but not sure which one (if any) will fit?

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_920291_langId_-1_categoryId_230505​

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_920349_langId_-1_categoryId_230505​

Thank you in advance

 

[ParaBag]

OK....perhaps a very stupid question! I am assuming that because it is a Narrow 7/8 speed chain, I should get the 7.1mm version (rather than 7.3). Does anyone else concur?