Three sides sealing is common product, and the customized heat sealing device is needed for the four sides sealing.

包装成品的形状为三边封或四边封。 三边封为常规产品，四边封需特殊定制热封器。

youdao

The fireproof cover is formed by combining a fire sealing and heat insulating device and a filter fume extractor.

防火罩由封火保温装置和过滤排烟装置两部分组合成。

youdao