No matter your configuration, you will need the Micro Hub. If you are using a Surefire Scout series light (or light that shares that mounting pattern such as the Streamlight Protac Rail) you will not need any additional parts. If you would like to mount a handheld light, you will need the appropriate sized ring mount. If you would like to mount a picatinny rail mounted light, you will need the Offset Rail. If you are using the Micro Hub in conjunction with a Laser device, the Light Wing (Left or Right depending on side) will mount the light alongside the laser system.