Sorry I have had to cross-post via uk.legal as I cannot get the diy
group on the bt server for some reason.

I am fitting pushfit flexi tap tails to kitchen sink - this is a
money-saving measure as I can't afford a plumber.
I've read up about them so I know to use pipe-cutter etc. but stupid
question time -
I bought them from Toolstation as a pair for monoblock tap - they are
different at the threaded end - they both have the same length of
threaded section, but the bit behind that is longer on one than the other.
I've searched the net but can't find out why - anybody assist please? I
really can't afford to mess this up!

Many thanks

Sorry once again to uk.legal for the x-post.