Vacuum tube: Borosilicate glass 3.3, 47*1500, 58*1800 Inner shell: ... stainless steel plate Outer shell: Color stee Detailed product description Vacuum tube: Borosilicate glass 3.3, Φ47×1500, Φ58×1800Inner shell: SUS304 ... heating solution as hotel, school, and public bath, etc. parameters Vacuum tubesTank Capacity(L)Loading Qty (20'GP)Loading Qty (40 ...