$600 is far too much for these drums.They look like Hoshino's to me,notorious for poor workmanship.Those lugs have 1/4-20 threads on the tension rods.Prices like that should be for a really rare set of MIJ's-Lava pearl double-bass set,or 13/14/18 /24 w-hardware.Or the chrome steel Apollo's.But people will spend $2500 on a friction powered tin rocket from Marx-