To attach flowcaps to flowtoys tubes, place the cap over tube, push and twist until flowcap buttons click into the tubing holes.
To detach, twist to release the buttons and pull.
Tip 1: Hold the cap closer to the top where the buttons are, twisting off. If you hold it closer to the bottom of the cap, you will not release the buttons.
Tip 2: It helps to use a bit of "monkey grease" (oils from your hands) or a tiny bit of vaseline on the parts of the tubes that interact with the caps and connectors. This prevents stiction and squeakyness, and generally makes interacting with your caps and connectors a more smooth experience.
You can find flowcaps on our website here: http://www.flowtoys.com/flowcap/