Tex 80 is considered a fairly thicker (heavier) thread (for heavier fabrics, heavy-sewing applications) rather than fine delicate sewing. 2500 yards in a spool.
If you’re sewing dense fabrics, heavy-duty materials (denim, leather, canvas, upholstery, outerwear, etc), or doing top-stitching, a Tex 80 thread may be appropriate.
If your machine is a domestic sewing machine, check whether it can handle such a heavy thread + appropriate needle size (e.g., size 18 or above) — some user reports mention needing larger needle and adjusting machine settings for Tex 80.