描述

The default of the upstream content is to send double plug-ins (most of them are this kind), and a few parts are single plug-ins. If you need a single plug-in, please contact customer service and remark, it cannot be universal.

The alarm bell of this button is divided into single plug-in and double plug-in, which cannot be used universally. If you need to buy an alarm bell, please purchase it accordingly, and note the color of the light and whether it has Braille or not.