6x AT&T MC-30 Microcassette Tape Incoming Message Cassette Answering Machine Go to amazon.com Related posts Top 14 best microcassette tapes mc-30: Which is the best one in 2022? FeatureAT&TMC-30Speed: 2.4 cm, 1.2 cm DescriptionAT&T Brand Microcassette used for the older versions of answering machines.