ScubaMax Spandex Sport Sock - Scuba - Snorkeling - Fins - Heavy Duty 6 Oz. (Black, One Size)

How thick are they?

Do these have a heel or are they like tube socks?

How long are these socks?

what about seams? Compare the heavy duty 6 oz. to other lycra swim socks? Need info from someone who wore the socks