9 track reel tapes

I came across a decent stash of 9 track reel tapes during my clean out. (4 cases, so maybe 50 or so of them) A while ago, I sold or gave away (don't remember) a whole bunch of the write protect rings for them. So I'm wondering, do those rings stop you selling the 9 track tapes on ebay, but I want to make sure I specify the correct status of the rings (that don't exist). Also, are these safe to bulk erase with an electromagnet? So far none of them have any data on them that I am worried about erasing, so I'm not planning to bother... but I want to know if it is safe or not in case I find one I need to. And finally, are all 9 track tapes the same? These were used on our General Automation Zebra machine. So will they work on any machine that needs 9 track, or only on other Zebras? -chris <http://www.mythtech.net>