There are sites that are now offering MRL and Teac tapes that use their name but in reality they are duplicating their own signals on tape from who knows what kind of machines. This is one example-https://www.ebay.com/itm/BRAND-NEW-1-4-7-5-in-s-MRL-Four-Frequency-Calibration-Tape/392363532341?hash=item5b5ab06035:g:XaEAAOSwUPxdQc2f
These are fake and also not accurate and basically they are rip off artist that use reputable names to sell their garbage. Since when does Teac operate an alignment tape facility in Germany? It is all junk waiting to steal your money. Get MRL tape from good dealers like JRF Magnetics or MRL themselves and don’t buy the 4 tone cheaped out tape as this will not be as good as the real thing. I have been using MRL tapes from the late 80’s.