CK quick screw connectors made of stainless steel are suitable for connecting plastic lines with defined hose inside and outside diameter combinations. These screw connections are used with very soft hoses, vacuum applications, liquid applications or with strong movements between hose and connection. As a rule these connections are used with hoses made of polyurethane (flexible), polyamide (stable), PE (economical, but kink sensitive) or PTFE (highly resistant). Tip: Most of our stainless steel CK screw connections are manufacture of the acid-resistant material 1.4571 (V4A). For cost reasons many suppliers use lower value, non-acid resistant stainless steel, e.g. 1.4301 (V2A). The material is a quality criterion!