What is an EFP?
An EFP is a copper warhead that, once detonated, is superheated, turning it into a molten projectile that can punch through almost anything — including M1 Abrams tanks and MRAPs. They are usually designed to be triggered by motion, remotely, or via pressure switches like other types of IEDs.
“EFPs are a kind of mine that has two special characteristics. One is that the mine can be deployed quite far away from the side of a road or wherever the target is,” said Dr. Michael Knights, a Jill and Jay Bernstein Fellow at The Washington Institute.
Knights has traveled throughout Iraq, Yemen, and the Gulf States and regularly briefs U.S. government policymakers, congressional committees, and U.S. military officers on regional security affairs.
https://taskandpurpose.com/tech-tactics/efp-explosively-formed-penetrator-projectile/