Developed in AE 139 by Bombs-R-Us®, the Double-A or Acme-Ashmun Shield Intrusion Mine could effectively penetrate an Acme-Ashmun Force Shield and deliver its deadly payload to the outer hull of the target ship. This is how it worked: Each Double-A Mine projected its own Acme-Ashmun Shield and when the mine shield made contact with the shield of the target, the two shields merged like the whites of two eggs broken into the same frying pan, allowing the mine to pass easily through the ship’s defenses. Bombs-R-Us discontinued the model in AE 143 due to low sales figures. What happened? In order not to undercut sales of its most lucrative product, the Acme-Ashmun Shield, Bombs-R-Us priced its mines so that they were within the reach of only the most “discriminating” buyer. In other words, the shields were so extravagantly expensive they were out of reach for 99.9% of the spacing public.