They allow visual checking of chambers and flames. Pyrex glass, protected with alloy mesh, provides large viewing area. Cast iron frame and housing. Automatic, spring loaded shutter.

• 允许视觉检查燃烧室和火焰。派热克斯耐热玻璃，合金网保护，提供大视觉范围。铸铁框架。自动弹簧负载门。