... logo accepted.Technical Data MODELSTB-ITB-IIProduct nameAll glass evacuated solar collector tubesEnvelop tube diameter47mm58mmInner tube diameter37mm47mmLength of tube1500, 1600, 1800mm1500, 1600, 1800mmSolar seletive ... max. hailstone25mm diameterLoad quanity 20GP/40GP/40HC47 x 1500mm tube: 4788pcs/10143pcs/11634pcs58 x 1800mm tube: 2700pcs/5400pcs/6000pcs All-Glass Evacuated Solar Collector Tubes