There are two classes of anvil type detonators, those which employ a No. 28 cart-ridge base, complete with percussion cap and anvil for their initiaton, and those in which a percussion cap is housed over an anvil in a recessed plug, which screws into the head of the detonator. These two classes are called the "Cartridge base" and "Anvil plug" clases respectively.

The cartridge base class was used in bombs which are now obsolete, whereas the anvil plug class is currently used in service bombs which employ the anvil type detona-tor.

Anvil type detonators of the cartridge base class are identifiable by a code of colors, associated with their delays. The code color is painted on the detonator head, and a corresponding colored washer label affixed to the head. The code of color is as follows:

Delay

Less than 1 second

1 sec. and less than 2.5 sec.

2.5 sec. and less than 11.5 sec.

11.5 sec. to 15 sec.

Blue

The anvil plug class of anvil type detonators is identifiable by a code of colors app-lied as a band, 3/8" wide, painted around the detonator head, and a correspondingly colored washer label, affixed to the plug, bearing the following particulare: type and mark number, date of filling, month and year, filling contractor's initials or recognized trade mark, lot number, and delay. The color code indicating delay is as follows:

Delay

Instantaneous

0.025 seconds

0.12 seconds

1.0 seconds

11 seconds

Blue