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 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.