 It has a streamlined casing capable of withstanding supersonic flight speeds.The weapon is long, with a diameter of about and a basic weight of about , except for the Mod 11 version which has a weight of approximately .The B61 is armed by ground-based personnel via an access panel located on the side of the bomb, which opens to reveal 9 dials, 2 sockets and a T-handle which manually triggers the "command disable" function.