Help identifying clasp? is this a slide barrel?

Trying to relearn everything I have forgotten. I researched it. Think that's what its called??
Lol but every time i think i know something someone else knows more.

So i defer to you wonderful people!

any help on country on the foil looking ones and this peculiar one that's triangular in shape and a white base with this caramel brown color over top? Time period? it measures 27" in length, its very heavy from all the glass beads.

Interesting that this necklace has those crimp beads and then the end caps. (I haven't seen that before, I don't think? (OR HAVE I?!?! LOL...Sorry all recovering from a head injury, So i am hoping to pick your brains, mines fuzzy!) i noticed some of that metal cancer stuff. have to get rid of that;

I got the AB stones figured out! WHOO HOO!!

 

Nice necklace. Don't know much about costume jewellery, but yes, a slide barrel clasp.

 

Check out this site:
http://imageevent.com/flippingtreasures/jewelrystyles/h2clasptypesh2

 

Excellent link Marie. Thank you!