为了便于搬运、安装，可以提供较小，较轻的外框以降低重量。

For ease of handling, installation, can provide smaller, lighter frame in order to reduce weight.

youdao

为了便于搬运、安装，可以提供较小，较轻的外框以降低重量。

For ease of handling, installation, can provide smaller, lighter frame in order to reduce weight.

youdao