Hitachi SX - 1981 - US
1964 - Maxell Electric lndustrial Co., Ltd. changed its name to Hitachi Maxell, Ltd
In essence Hitachi Cassette Tapes are Maxell rebranded cassette tapes.
In this case SX-C90, a tape manufactured circa 1981, it is fairly safe to assume this tape is none other than a re-branded Chrome Bias Maxell XL-II-S.
These are very rare tapes. Inventory is very limited.