DENSO spark plugs sales are globally increasing since it developed an Iridium Power which equips world's smallest 0.4mm Iridium center electrode. At this time, DENSO has successfully been supplying an Iridium Power"IU27D" for Suzuki Big Bikes. They are HAYABUSA1300 and B-KING. They equip 1340cc engine with twin fuel injector, titan valve etc.
Suzuki Genuine P/N for IU27D is 09482-00557.Also colder heat range IU31D is 09482-00559.

For aftermarket, IU27 and IU31 can be used instead of IU27D and IU31D respectively.