A-type detonator
From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
A-type detonators are used as a fuse for an explosive, such as G-4. They can be time-delayed or manually triggered.
Typically, A-type detonators are kept in cases of 12 with slots labeled A-1 through A-12; they are in small arms lockers onboard a battlestar. (Water)