Giotto Robercolor White Dustless Chalk. Box of 100: Amazon.de: Stationery & Office Supplies
Lyra Blackboard Chalk White Pack of 12) : Amazon.de: DIY & Tools
KOH-I-NOOR 5343 - Chalk holder made of metal for round 9-10 mm chalks, black - 3 Pieces : Amazon.ca: Everything Else
Jovi Classcolor Blackboard Chalk, Low Dust, Very Good Colour Dissipation, Easy Wipe Clean, Diameter 0.9 cm, Pack of 10 in White in a Box : Amazon.de: Toys & Games