Master Airbrush&reg; Brand 1/8" BSP Male to 1/4" BSP Male Fitting Conversion Adapter Nipple, Connector for Airbrush Hoses and Compressors Master Airbrush Brand Airbrush Fitting Conversion Adapter for compressors, airbrushes, hoses, hose splitters and manifolds Airbrush Fitting Connector Adapter Nipple: 1/8" BSP Male to 1/4" BSP Male Screw the adapters 1/8" BSP male thread side into a 1/4" BSP female fitting to convert it to a 1/4" BSP male size thread or vice-versa The 1/8" BSP and 1/4" BSP are the most common fitting sizes used for compressors, airbrushes and hoses The adapters 1/8" BSP hose thread size is the most common hose fitting size used for many popular airbrush brands like Master and Iwata