Spark plug Denso

ideally suited for a powerful spark paired with a long service life and better starting behavior. Denso IW20 Iridium spark plug for BMW two-valve boxer models with dual ignition or Siebenrock Big Bore Kit 1070cc Art.Nr. 110110 or Big Bore Kit 1070cc Touring Art.Nr. 1101110.
Mandatory for the lower spark plug is the spacer ring article 1212000!

Or as an alternative to:
WR5DC 1212146
WR6DC 1212145
WR7DC 1212485