Pneuflex' SPP 04 model is 4mm tubing stainless steel 316 plug push to connect fittings, used to plug unused tubing of pneumatic push in fittings. Common uses can be found in food, dairy, medical and chemical industries.
316 Stainless Steel Push in Fittings
SPP 04 | 4mm Tubing Plug Stainless Steel 316 Push in Fittings