This is a half pound (227g) reel of artificial round sinew hand sewing thread. This thread is a modern replacement for sinew or 'catgut' thread.
Artificial sinew is often used to stitch up historical leather craft projects and those with an American Western style. It teams up very well with veg tan tooling leather.
This is a large reel, standing 11cm tall (4 1/4") The thread is very chunky and quite heavy weight. We'd suggest that you use No 2 Needles to stitch this this thread. It's heavily waxed and very natural beige colour.