If you read the reviews, one picture shows it a fair bit larger than 5/16". That is one of the problems with Dyneema in that they make several different fibers. I'd have to look it up to recall which one we use but the one we don't use is about 20-30% less in strength. The one we like should be around 21,000 lbs. rated for 3/8". Sometimes they sneak it up a bit higher by listing 10mm as 3/8" and the larger diameter will push the breaking strength up higher making it appear that their 3/8" is stronger than other 3/8".
If you can verify the diameter somehow, it should be fine for what we do.