BSP Plug gauge Specification: ISO 228Manufacturing Range: 0.0625″ to 6″ BSP Ring gauge Specification: ISO 228Manufacturing Range: 0.0625″ to 6″ BSPT Plug gauge Specification: IS 8999 / ISO 7-2Manufacturing Range: 0.125″ to 6″ BSPT Ring gauge Specification: IS 8999 / ISO 7-2Manufacturing Range: 0..125″ to 6″