EC3 connectors for RC. Pkg has 2 blue mating housings & 4 Gold-plated mating connectors. Note: The Blue connector that goes on a Battery pack is the one with the narrower blue tips (more space between them). The Blue housing with wider tips goes on the Charger or motor. Also, the blue tips with the squared end are typically POSITIVE (+ Red wire); the Semi-Circle end is typically NEGATIVE (-). Original part ref. # EFLACE303. BULK PRICING AVAILABLE - see quantity options.