 It used a composite core of 4.2kg Pu-239 and 6.8kg 90% enriched U-235  and had a nominal yield of 30 kilotons.The bomb was delivered from a Tu-4 and Tu-16 aircraft.A tactical weapon based on the RDS-4 was also used on September 14, 1954 during Snowball military exercise near Totskoye (similar to Western Desert Rock exercises), when the bomb was dropped by the Tu-4 bomber (the reverse-engineered Boeing B-29).