Use of refrigerator foam, Italy imported equipment foam, high-pressure injection foam layer to more fully, more uniform density, high rate of obturator, better insulation effect, a refrigerator factory test equipment, the 72-hour high (+50 degrees, 24 hours), low (-40 degrees 24 hours) and temperature patterns of aging test pilot, the quality is always in a state controlled to ensure that the results, thicker insulating layer of 55mm ± 3mm, can be adapted to the alpine region