Electro-Harmonix: "the EL84EH tube faithfully recreates the classic Mullard design. Tri-lam plate material and selected screen wire increase thermal dissipation. The EL84-EH tube is a remarkable reproduction of a vintage tube that is capable of maintaining its sweet and musical tone under any voltage conditions." 
Review: " For most applications this is a good bet. The sound of these tubes is very smooth when biased correctly. Tonally, it’s hard to go wrong. They are pleasant to listen to and have the creamy overdrive most people look for in an EL84. They hav...

These tubes have a slightly larger diameter than other EL84 tubes so they can not be installed into some '90's era Marshall DSL201 or DSL401 amplifiers, some '90's era reissue Vox AC15 amps, and Bad Cat amps.