7.69—Approval marking.
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.