Physical Description The M904 (series) fuze contains approximately 1 1/2 ounces of tetryl in the booster, which is located at the base of the fuze body. The entire fuze weighs about 2 1/3 pounds and is 9 1/4 inches long. The  M904E4  is  a  thermally  protected  fuze.  It  is especially    designed    for    use    with    the    thermally protected  Mk  80  (series)  general-purpose  bombs  and the thermally protected M148E1 adapter booster. This significantly increases the cook-off time (table 1-1) of the bombs subjected to intense heat or flame. REVIEW NUMBER 1 ANSWERS A1. A fuze controls bomb detonation. A2. The   time   or   number   of   vane   revolutions needed  for  the  firing  train  to  align  after  a bomb is released is the arming time. 1-4 Item Ordnance Fuze/Adapter Booster Average Reaction Time (Min & Sec) Shortest Reaction Time Bomb Initiated Reaction Fuze  Booster Initiated Reaction* Bomb H6  and PBXN 109 filled Mk 82, 83, 84 unprotected All 3 + 30 2 + 30 Deflagration to explosion Deflagration to  detonation (after  5 minutes) Mk 82 Mods/ BLU-111 M904E4  with M148E1 Adapter, FMU-152, FMU-139 10 + 00 8 + 00 Deflagration Deflagration to  detonation (after  12 minutes) M904E2/E3 with M148/T45 6 + 00 5 + 00 Deflagration to detonation M148T45 (no fuze) 3 + 04 Deflagration to  detonation (denotation may  occur after  5 minutes) Mk 83 Mods/ BLU-110 thermally protected M904E4  with M148E1 Adapter, FMU-139/B, FMU-152 10 + 00 8 + 49 Deflagration Deflagration to  detonation (after  12 minutes) Mk 84 Mods/ BLU-117 thermally protected M904E4 with M148E1 Adapter, FMU-139/B, FMU-152 10 + 00 8 + 45 Deflagration to  detonation (after  12 minutes) *  Fuze or booster initiated reaction.  Frequency of detonation reaction is small. **  Chips in exterior coating and/or groove for retarding fin cut to bare steel do not change cook-off time. Table 1-1.—MK 80/BLU Series Cook-Off Times