Adapter to join 1/4" tube to 1/4" tube - typically needed when extending a length of pipe to get to your fridge.

These can also be used to make an effective repair to existing tubing where a small leak has occurred - subject to the tubing having a bit of play (you obviously need to cut out the damaged section).

If you a cutting a pipe to insert a new section (a major leak/repair for example), then you will need TWO adapters as well as enough tube to bridge the gap.

Brand may be either John Guest or DmFit - both brands are widely used push-fit connectors.