Screw outdoor branch box: Usage and properties: 1) Suitable for the connection between branch line and the communication line in the city, county and countryside 2) The body of the case is made of aluminum alloy castings, smooth and stable 3) The reasonable structure of right-opened case-cover and reversible block leading to better airproof and easy opening or operation Environment: 1) Environmental temperature: -55°C ~ +55°C 2) Relative humidity: 3) Atmospheric pressure: 70 - 106KPa Main technical indexes: 1) Insulation resistance between the end and the box: ≥5 x 104mΩ 2) Contact resistance between the lead and the end: ≤5 x 10-3Ω 3) Voltage-resistance strength: non-puncture, no arc-over 500V AC/1min Wall inlaid indoor branch box: 1) Suitable for the connection and distribution between indoor communication cables and the user lines 2) The body case is made of armor plate with high quality, with spray-painted face, smooth and stable, anti-corrosion 3) The reasonable structure of right-opened case-cover and reversible block leading to easy opening or operation Dome branch box: 1) Suitable for the connection between branch line and the communication line in the city, county and countryside 2) Has the ability of avoiding thunder attacking and over-current or over-voltage 3) Apply the vacuum glass tube to improve the insulative property and observe the inside conditions easily and also has the special grounded device