Bucky Balls 1) Different size: 3mm,4mm,4.8mm,5mm,6mm...10mm 2)COlor: NI,BLACK-NI,GOLD,SILVER, AND colorful 3)Delivery ... magnet balls.Diameter: 4mm,4.8mm,5mm,6mm,7mm,8mm,9mm,10mm(tolerance+/-0.02mm)Color: gold, silver,black nickel, blue, red ... ,yellow ,green ,orange or othersMagnetic force(N35grade):5mm 5000-5400guass,6mm 5400-5800guass ...