Dismounted reconnaissance troop
A dismounted reconnaissance troop (DRT) is a reconnaissance unit found within U.S. Army RSTA squadrons that are part of infantry brigade combat teams (IBCTs). While a RSTA squadron serves as the primary reconnaissance element for its parent brigade, the DRT serves as the specialized reconnaissance element for the squadron when conducting clandestine reconnaissance and surveillance.
Source: Wikipedia — Dismounted reconnaissance troop (CC BY-SA 4.0)