This rocket is a rare, air-to-ground, anti-tank version of the R4M, which was originally designed as a German World War II unguided air-to-air rocket for use against Allied bombers. The smaller warhead used in the original configuration was replaced in this anti-tank version with a warhead derived from the shoulder-fired Panzerschreck infantry weapon.
The U.S. Army Ordnance Museum transferred this rocket to the Smithsonian in 1989.
This object is on display in Rockets & Missiles at the Steven F. Udvar-Hazy Center in Chantilly, VA.