ACOUSTIC RESEARCH AR-3A TWEETER REPLACEMENT-RE. This tweeter is a direct drop in to the existing tweeter opening, using the original tweeter screws. A special crossover has been added to the rear of the tweeter so that the performance closely matches the original. This sale is for a pair of Acoustic Research AR3a Tweeter copy by Vintage AR which I bought but no longer need. The brand is Hi-Vi RESEARCH and is for the rear wired models. Never installed and never used so its like new.