This single-seat aircraft was designed by Henry Kjellson, and was given the name of "Tummeliten" (Little Tom Thumb), but was lovingly refered to as "Tummelisa" by the pilots who flew her. The "Tummelisa" was the name of Tom?s female counterpart. Eleven of the Tummelisas were transferred to the Air Force in 1926, and were used as advanced trainers. As advanced trainers, they got the designation O-1. The last Tummelisas aircraft can now be seen at Flygvapen museum.