... .1X10-6 k-1Outer diameter of tubesΦ47±0.7Φ58±0.7Inner diameter of tubesΦ37±0.7Φ ... solar energy fully, there is no need to wait and the water is available immediately, high level ... the current products mainly include: diameter: 47/58mm, and the length is 1800mm, but we can also provide ... faster. Efficient tube, the super absorbing, thermal efficiency is high, warming faster, in the same light conditions, ...