Sanitary Manhole Cover(pressure manhole, sight glass) Export to USA, UK., tank manufacturer since 1996. ISO9001-2008 ... APPROVED! Sanitary Manhole Cover(pressure manhole, sight glass)Dimensions: 250*100mm -600*120mmThickness: neck 5mm, cover 4mmPressure: -0 ... dairy and chemical industry, Sanitary Manhole Cover(pressure manhole, sight glass)