The EFT Triple is best used for old bull bugles and grunts. EFT "Extended Frame Technology" was created by extending the frame upward and inward creating a simple yet effective system for securing the call in place for a perfect fit every time. A great fit equals a great sound, hear the EFT difference! The EFT Triple is best used for old bull bugles and grunts. EFT "Extended Frame Technology" was created by extending the frame upward and inward creating a simple yet effective system for securing the call in place for a perfect fit every time. A great fit equals a great sound, hear the EFT difference!