Spark Plugs NGK Iridium IX Spark Plugs BKR5EIX-11 # 5464 Set of 4 These are leftovers purchased/imported from AliExpress because my personal Subaru Pleo started making a popping sound at low speeds. Idle became stable after replacement. Install by hand-tightening until resistance is met, then tighten with a spark plug wrench another 1/2 to 2/3 turn. Wrench size is M14. Suitable for Subaru R2, Sambar, Pleo, etc. Many other manufacturers are also compatible. The following site is convenient for compatibility checks ↓ https://www.rakuten.ne.jp/gold/auc-138onlineshop/NGKPlug/INDEX.html