With competition-level LiPo batteries mostly available with either 4mm or 5mm plugs, mix and matching different brands with various sizes plugs might an authentic challenge. Arrowmax had tested the rescue by establishing a 5mm to 4mm down-sizing layer. Various along with other comparable products and services in the marketplace now, the layer functions placing to the 5mm plug on LiPo and efficiently changing it to 4mm. No soldering and extremely convenient to move from pack to pack. You will definitely keep your asking cable and ESC connection with similar 4mm plugs and still to use LiPo with 5mm conncetion. They come 24K silver plated for optimum conductivity.