Tape - Scotch 7".
I remember being quite intrigued that the 3M logo (at bottom of box) stood for Minnesota Mining & Manufacturing - quite a mouthful.
Things aren't quite as they appear with this 'tape'. 8mm cine film was the same width as the standard half inch audio tape and this box is in fact full of cine film on the 7" spool. The reverse also applied and we used the 3" spools, that Kodak sent developed movie film back on, for audio tape. The contents of 1 x 7", 2400' double play audio tape reel would make 6 x 3", 400' reels - it was cheaper to do it this way round!
