Check Valve size:1/2" to 4" Standard :ISO, GB, DIN, etc. Material quality: 304, 314L, 304L,316 Product Name:Sanitary Threaded Check ValveStandard: adopt ISO, GB, DIN, etc.Material quality: 304, 314L, 304L,316size:1/2" to 4"Apply: high-accuracy fluid equipment such as pharmacy,dairy food,beverage,beer,wine,biology etc projects.