The Series IV was the last of the monkey coffins and was sold from 1984 until 1994. It was the same size as the previous models with the most obvious difference being the new full height grill which now only wrapped halfway down the sides of the box. The speakers were made up of one 10" woofer and two 3" tweeters just like all previous models (give or take a 1/2"). The Series IV lost the adjustment dial for the reflecting speaker that was found on the III. Despite the similarities, the whole cabinet was a new design using a ported woofer enclosure and placing both the forward and rearward facing tweeters on the forward outside corners of the cabinets. This meant that speaker placement became far more important than before. Sell as is