Blister Rounds

"The Blister Rounds increase the hull damage of Explosive weapons by adding fragmentation ordnance to the warheads."

General
Blister Rounds boost Explosive weapons by increasing their health damage. It can be used only on Demon Corps Hulls.

Advantages
Blister Rounds are particularly effective against Iron Star Company Hulls and cruisers which often have heavy armor equipped. They also excel against modules with limited shield capacity.

While they have a mass requirement that is similar to the health damage bonus, the fact that most weapons become less mass-efficient at higher levels merits the use of this special to improve the efficiency of your weapons.

Disadvantages
Blister Rounds are not useful against shielded enemies because they do not give a shield damage bonus.

AM Warheads are more suitable for your weapons overall because they cost less mass and have the ability to multiply damage with the extra splash radius. However, Blister Rounds are still popular on weapons with small AoE such as Manifold Missiles.

Trivia

 * This is the first armor damage weapon boost ever released.