properties /measurement

How thick the electrode's firing tip is, as a length — and the number a fine-wire plug is actually sold on, because a thinner tip needs less voltage to fire. Published per electrode by every maker: NGK gives "Center Electrode Size: 2.5 mm" for the plain nickel BKR6E-11 and a 0.8 mm iridium centre for the ILZKR7B-11S; Denso gives 0.4 mm for the IK20 and a 0.7 mm 360-degree laser-welded iridium tip for the SK20HR11; Bosch's table distinguishes "Centre electrode platinum, diameter 1.1 mm" from "diameter 0.8 mm" as separate published designs. IT IS MINTED PRECISELY BECAUSE THE CLASS QUESTION WAS ANSWERED BY A FOLD: with "iridium plug" resolved to a value of `electrode_material`, this is the number that would otherwise have been lost with the class — a 0.4 mm iridium tip and a 2.5 mm nickel one are six times apart and the whole price difference lives in that ratio. [The b154 rule, H2-f16: check the parent's completeness at the moment the fold is made, not after.] Qualified by `electrode_side` for the same reason as the material, and distinct from the spine's `diameter`, which is the product's own overall size.