The Streamlight ProTac Rail Mount HL-X Pro is a lightweight, low-profile long gun light that produces 50,000 Candelas of power. Its unique Jack-Cap tail switch offers the user the operational convenience of switch redundancy with a push-button operation or a remote pressure switch operation. The ProTac Rail Mount HL-X Pro features Streamlight’s Multi-Fuel functionality. It can use either 2 CR123A lithium batteries or Streamlight’s SL-B26 Rechargeable USB Battery. The ProTac Rail Mount HL-X Pro has a rail-grabber with thumbscrew that easily attaches to Picatinny rails with no tools needed and is compatible with MIL-STD 1913 rails and M-LOK compatible rail systems. The Streamlight 88126 is the CR123A System, the 88127 is the USB Rechargeable System, the 88128 is the light only with the CR123A batteries, and the 88129 is the light only with SL-B26 Rechargeable battery.