B28 (nuclear weapon)/Definition

Bomb in use for 33 years (1958-1991), 4500 built in 20 variants with multiple Permissive Action Link types over lifetime; yields from 70 Kt to 1.45 Mt; replaced by B61 and B83 bombs; W28 warhead was same physics package and British Red Beard was a derivative; 1-point safety problem with primary stopped initial production run.