I see you have the same issue as others on the internet. The M1 Timer Detonator, no one can figure out what that is, as it is not listed at all in any public document. The picture everyone uses is a fuse from a Mk82.
Here is a discussion we had last year about this and what it might be:
https://forum.juhlin.com/showthread.php?p=85615&nojs=1
I know Kevin Dockery is on Facebook (I'm not), maybe some wants to ask this question thru the Facebook page to him or directly to him.
I'm on Page 113 so far.