30x6 means 30 min on all 6 sides. Normally safes are installed bolted to concrete and sometimes positioned in a building so only the front or possibly sides are

30x6 means 30 min on all 6 sides. Normally safes are installed bolted to concrete and sometimes positioned in a building so only the front or possibly sides are easily accessible to attack, so often the door is far more attack resistant than the rest of the safe. This saves money and mass.