Shelly EM (X1) is a dual meater channel (max 50A for channel) for measure the consumption of your home.
Shelly EM (X1) also provide one output for drive max 5A, useful for relay of lighting.
You can buy Shelly EM (x1) with one 50A probe for example here.
You can by and adaptor for install Shelly EM (X1) in your electric cabinet for example here.
Please pay attention to the direction of the wire inserted in the split core current transformer, see image below.
Input from K, Output from L, there is the label on the split core current transformer.
For more info see the tutorials that are present on Internet (YouTube and similar).
Tutorial in Italian language see for example here or here.
Per integrare Shelly EM (X1) in Home Assistant guarda questo video.