Used on b-52 aircraft. 2b single mounting facility thread class 3.390" overall length 1.280" overall width 32 single mounting facility thread quantity per inch in-line, cam actuated unc single mounting facility thread series
2b single mounting facility thread class 0.370" overall length 1.700" overall width 56 single mounting facility thread quantity per inch rectangular indicating unc single mounting facility thread series
2a single mounting facility thread class 0.375" single mounting facility thread length 3.905" overall length circular wafer, bushing mount unef single mounting facility thread series
2a single mounting facility thread class 0.375" single mounting facility thread length 2.427" overall length 1.609" overall width circular wafer, bushing mount unef single mounting facility thread series