I don't like how that product description declares their product will increase the power of the gun and then mentions how 10m guns used to have two springs. They didn't have 2 springs to make them more powerful. They had two springs because they were coiled in opposite directions and so the theory was that their rotational energy will balance each other and make a smoother shooting experience. Others can say better than I how well that idea ended up working in actual practice.
If you want more power, use a spring with a thicker wire and know that you will probably lose some accuracy.
