Classes of Internal Threads and Classes of Cutting Taps Sizes Description of products Basic Pitch Dia. (+)μm ISO 2X ISO 1 ISO 2 ISO 3 ISO 1 ISO 2X ISO 2 ISO 1 ISO 2 ISO 3 ISO 3 ISO 2X ISO 2X Internal threads 5H ISO 1 ISO 2 ISO 3 Internal threads 6H ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 ISO 2X ISO 1 ISO 2 ISO 3 Information Technical Technical-14 785