30 CFR § 7.69
Each 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
(d) The replacement battery types if the unit has replaceable
(e) A warning placed next to the charging connector that the battery
only be charged in a fresh air location if rechargeable batteries are
(f) A warning that the unit is compatible only with detonators that
(1) Fire when an average of 1.5 amperes is applied for 5
(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