Japanese 8/0 Toho round seed beads have a very consistent shape and size. They are the most popular size of seed beads and are available in 100's of different colors. They are designed with a larger hole than other seed beads which allows for more pass-throughs for thread.
The larger hole also means you get more beads per gram. (110 to 120 Beads per gram)
Silver Lined Dark Peridot