This is the Castle Link Quick Connect from Castle Creations.
Installs between ESC and receiver
Y-harness with wire to connect to Castle Link
Can leave connected for easy access for Castle Link without
disrupting receiver or ESC
Detects the presence of Castle Link adapter
One Castle Link Quick Connect
One piece of clear heat shrink
BOX DIMENSIONS: 3.00" W. X .75" H. X 5.75" L.
BOX WEIGHT: .02 LBS.