They measure 2.5 mmx 5 mm with two .8 mm holes.
These beads are not simply coated crystal, but actual colored glass with various coating options such as opaque, picasso, luster, and AB. Superduo beads are 2-hole seed beads made from Czech glass, which are pressed for guaranteed size and dimensional stability. Super Duo Beads gold lustre 2.5 mm x 5 mm 24 gm tube.