This is the Great Planes ElectriFly|
3.5mm Male Bullet to 4mm Female Bullet Adapter.
Connects a motor with 4mm Male Bullet Connectors to an Electronic
Speed Control with 3.5mm Female Bullet Connectors
Three Great Planes ElectriFly 3.5mm Male Bullet to 4mm Female Bullet
Connector #1: 3.5mm Male Bullet
Connector #2: 4mm Female Bullet
Weight: .08oz (2.33g) each adapter