The cap is an open valve that is closed after bolted on.

No, sir, we came all the way down here because we're losing our atmosphere through an open valve.

In the wrong hands, he said, it would be simple to crash one into a building or open valves to release clouds of deadly gas.

Start with the valve open and without using the ice bath.

Air flows at considerable speed through the open valve.

A break in the belt may destroy the engine if pistons touch open valves at top dead center.

If you just blow it out, gas'll still come flooding out of the open valve.

Art Wiltessa pulled a lever and spun a valve wide open.

She hooked her patient to a bag of saline and thumbed the valve wide open.

The soft parts are bright red and many tentacles protrude from the open valves.