Digi, a military working dog from the 11th Wing Security Support Squadron, demonstrates his ability to incapacitate people on command at the library at Joint Base Andrews, Md., July 23, 2014. Staff Sgt. Staff Sgt. Lucas Tripp, an 11th SSPTS MWD trainer, donned a protective training suit and refused to cooperate with an MWD handler during the demonstration. The library hosted the MWD demonstration as part of its "Paws to Read" summer reading program, which runs through Aug. 9. (U.S. Air Force photo/Staff Sgt. Torey Griffith)