Complex sentence: Three models were announced, the 3340-A2 with two drives and a controller and the models B2 (two drives) and B1 (one drive) which could connect to the model A2 to a maximum of eight drives.
Split into simpler sentences: Three models were announced, the 3340-A2 with two drives and a controller, the models B2 (two drives) and B1 (one drive). B-units could connect to the model A2 to a maximum of eight drives.