This is a set of Revtech XT90 Connectors, It contains 1 female and 1 male connectors.  Connectors have 4.5mm pins and are made from high-temp Material and gold plated 

spring connectors inserted in the injection mold at the time the connector is formed they offer low resistance, high-amp capacity connection and are the ideal power connector for high current applications.

Features

• Low resistance for high current capacity Perfect for Drag racing. 
• Protected to avoid shorting and reverse polarity
• Superior technology suited to today's high power applications