EUROTEK STORE › NGK Spark Plug EG - (VORTEX MINI ROK) Image 1 of 1 NGK Spark Plug EG - (VORTEX MINI ROK) $15.00 NGK Spark Plug - EG Range.These are the only spark plugs permitted to be used in the VORTEX MINI ROK Engine in Australia. Type: B9EG B10EG Add To Cart Added! NGK Spark Plug - EG Range.These are the only spark plugs permitted to be used in the VORTEX MINI ROK Engine in Australia.