Possibly Cotton - at least that's what it feels like, but there are no labels or other indication as to the makeup or size of the thread.
The only labels that came with the thread are at the bottom or each spool indicating color (see pictures). In this case, they have a color number of 67109
Thicker than normal thread (see smaller green spool which is ONLY pictured as an example for perspective - smaller spool is NOT/NOT included in the shipment).
THREE STRAND TWIST? (see picture - also pictured in comparison to the green thread. I've never dealt with spools of embroidery thread, so I'm not exactly sure about the number of strands - each of the three separate strands appears as if they could be further divided, but -- not sure.)
The plastic bags (packaging) came on each of the spools - one was removed only for pictures, then returned to bag.
No returns.
No international shipping.