Nippon Denso do an iridium plug (IX 24 B) with a 0.4mm centre electrode (NGK is 0.6mm) comes at a price though, £15ish, I have one on order.
I have to admit, when I went in to the garage to measure a spare NGK I sat on KLX for a minute.
KLX and LS plugs are the same fitment.
Clive W