The RaceFlight Bolt 4n1 electronic speed controller (ESC) provides the power of BlHeli_S performance in a slim package. This makes your electronic stack slim, and generally eliminates the need for an additional PDB. The 4n1 ESC performs great and helps clean up any build.
It is also extremely easy to install. It is compatible with 4s through 6s batteries and has a built-in current sensor that hooks up directly to the Revolt to provide mAh information. The whole 4n1 ESC pins directly to the Revolt flight controllers and also sends voltage.