U p for sale is a Vintage Rare Acoustic Research AR 401-28 10″ Woofers / 4 1/2″ Mids / Dome Tweeters / Crossovers Includes Original Screws and Signage all in Working Condition. Lot came from Heathkit AS-2A Acoustic Suspension Loudspeaker System Speakers. Speakers were tested at Soundwerks Vintage Audio in Phoenix AZ. Key Specifications (AS-2A / AR-2). 3-way, Acoustic Suspension Loudspeaker System. Two 5 cone midranges. 1.375 dome tweeter (some variations used different tweeters/supertweeters). L-C network, 1000 Hz crossover point. +/- 5dB, 40 Hz – 15,000 Hz (or up to 20kHz in some versions). 15 ohm 20% 4 watt tweeter level control. My descriptions and numerous clear pictures are absolutely accurate and I do my best to be perfectly clear and concise.