Where to buy it:
XT60 connectors (HK)
XT60 connectors (DX)
Nylon T-Connectors (HK)
Nylon T-Connectors (DX)

If you’re making the transition to XT60 connectors but still have lots of deans t-connectors then this is a good way make use of what you got.  With this method, you don’t need any wires.  You’re soldering them directly to each other.  Positive to positive, negative to negative.

You’ll need to bend and twist the positive pole on the t-connector to make it fit with the XT60 side

Line up the connections.  They should be snug

Solder them together

To prevent the positive and negative from arching and causing a short, fill the gap with hot glue.

Use some heat-shrink tubing to finish it off.  If you don’t have some, use electrical tape.

Here’s a few I made.