This is a RCPROPLUS product. Supra-X series.

These connectors feature a large, low resistance surface for efficient power transfer, with waves built into the housing to help dissipate built up connection point heat. 24K Gold Plated bullet plugs with a recessed wire cavity and solder windows provide hassle free assembly, making these connectors a great solution for the high current and high voltage demands of today brushless motors. Also, when the male and female ends are connected together, they click letting you know they're tightly joined and ready to perform.

Features:
Protective base eliminates any need for heat wrap
Use with brushless motor systems
Recessed wire cavity and solder windows
Large, low resistance contact patch
'Click' connection
Hassle free assembly