Essentials By Leisure Arts Preciosa Rola are the first traditional Czech seed beads produced with the newest quality cutting technology. Enjoy integrating the beautiful colors and finishes into your design while taking advantage of the increased precision of the cylindrical shapes with thick curved edges and large holes. 6.2mm Opaque Black Matte 15gm- Glass cylinder bead is 6.2mm. 15 grams per bag.