Section 7.69 - Approval markingEach approved blasting unit shall be identified as permissible by a legible and permanent marking securely attached, stamped, or molded to the outside of the unit. This marking shall include the following:
(a) The assigned MSHA approval number.(b) The maximum blasting circuit resistance.(c) A warning that the unit's components must not be disassembled or removed.(d) The replacement battery types if the unit has replaceable batteries.(e) A warning placed next to the charging connector that the battery only be charged in a fresh air location if rechargeable batteries are used.(f) A warning that the unit is compatible only with detonators that will-(1) Fire when an average of 1.5 amperes is applied for 5 milliseconds;(2) Not misfire when up to an average 100 amperes is applied for 10 milliseconds; and(3) Not fire when a current of 250 milliamperes or less is applied.