Description: Distribution transformer Service condition: 1.altitude: not over 1000m, 2.ambient temperature: -5 degree to +40 degree 3.relative humidity: less than 85%, at 20 degree 4.the product has passed the direct vibration test with the intensity of 0.4g three sine waves, equivalent to nice-degree earth quake on the richter scale. 5.This product can be used in condition of pollution.