If u have the Sena SRL2 and a ordered a GT AIR 3 this is an adaptor for you. Not very easy to install but not especially hard. There is a youtube video with a basic guide. if you want the cables out of the way you have to try a bit more. The plastic parts assembly well together but they extend a bit and you need a bit of careful handling when you put on or off your helmet. However it is better than putting a large external unit.
规格图表
A.为获得头盔的适用尺寸,请将卷尺在耳上约 1 cm 处,围绕头部最宽处一圈。
将所得测量值对照尺寸表。