The Teac HX series is probably a fairly long-lived series of tapes which we own a fair amount of. They were available in a variety of lengths (which I’ve collected, although unfortunately, there are labels over some of the covers) and in plastic sleeves as well as paper. It seems they changed to paper later in order to reduce costs.
Quite cool isn’t it? They just changed the colour and the number, basically. The E-120 and E-240 jackets are plastic and seem to have held up better than the others.
The cassettes inside all have the same shell shape, although the central label area is already pre-labelled with a header (colours as per length coding above). The writing label itself is slightly shorter as a result (see the one pasted on the E-120 and E-180 sleeves).
Later HX cassettes did away with the metallic header label and introduced the S-HGX/X-1 style hub reels.
The reels are a classic Teac design as well.
As is the bottom. You’ll soon recognize these rectangles, both in vertical and horizontal orientation as being “characteristically Teac”.
Finally, the spine label is unruled, and mostly clear for marking. Note the manufacturer’s printing in thick blue-grey-white ink. It has been written over with paint marker (as part of a tape-inventory system).
Interestingly, some of their cassettes (in my collection, only the E-240) feature nylon rollers. The others use the polished stainless steel as most others do.