Open barrel splice for inline and parallel splicing of wire. See video and selection chart (in the product photos) for details on how to properly splice.
Splitting one wire into multiple wires can be done in many ways, this video shows how to splice wires using an open barrel splice. Common applications are sensor ground wires & 5 volt reference branching out to multiple sensors, 12v power branching to injectors as well as many others.
Red handled crimpers in video can be found by searching for " Delphi 12085271 "