Grenade part? What is the black plastic part?

[bartshop62]

I found this grenade part. Metal detecting in the site of Part of a 1920s Us army air field. Practice training base and part of a base too. Did they use this grenade part for practice? It is to the army air field base Military or civilian? What is the black plastic part and the fabric? Is this grenade part fuse. a fake dummy replica toy reproduction or a real explosive weapon military grenade? It says CTS what does that mean?it was 7 inches deep next to a wood. Last picture is when it was dug at night.
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[Milo006]

Looks like the top of a smoke canister.

 

[Kenosha Kid]

CTS (Combined Tactical Systems) ~ less than lethal munitions; i.e., smoke, flash bangs, etc.