The BT lanyard we supply with all Lummi lights is Strong.
It is made from stainless steel wire, I forget how many strands but its allot.
If you were to put on your finger a pull I would suspect it could cut right through with enough force. Think Cheese wire
Only reason for it to fail in normal use is if it were to get cut / frayed. This as with any lanyard requires periodic checking & replacement if necessary.