The Keystone LB-6 and LB-7 were 1920s American light bombers, built by the Keystone Aircraft company for the United States Army Air Corps, called Panther by the company, but adoption of the name was rejected by the U.S. Army.
Keystone LB-6
XLB-12 prototype
XLB-12 port-side view
Keystone Aircraft Corporation was an early American airplane manufacturer.
The first Keystone B-3A bomber built, serial number 30-281