CF series are also called con-flat flanges.The high sealing effect and the low leak rates performance of CF flange connections is a result of gasket material.When assembling the CF flange connect,the knife edge is pressed into the flat copper gasket and force the seal material both axially as well as radially outwards to the flange.The material is enclosed and cannot flow even at high bake-out temperature.Due to this deformation of the seal such connections may sometimes stick together.They can be easily separated with a special tool or screwdriver.Offered in both rotatable and non rotatable verions with through holes and tapped bolt holes.Metric tapped holes and untapped holes flanges are identical products.UNC or UNF or other tapped holes can be ordered as specials.