Modification update with midrange upgrade, it is our redesign which makes a much superior audiophile speaker, which makes for a perfect balance between bass midrange treble, (original midrange driver was too squaky sounding Replacement driver, 2" dome design, more natural voice response, (Dayton Audio RS52AN-8) Round Frame fits existing holes- sealed back (Remove Boston Mid"cup") (Includes few (6) crossover parts to adapt circuit depending on speaker, Boston T-830 version) other crossover parts for woofer and tweeter update, circuit easy modification to do and this makes an amazing audiophile speaker Condition #10