This is a set of 7 plastic wrap cores. Perfect for crafting! Long ones: 4 pieces, 30.6 cm long Short ones: 3 pieces, 22.8 cm long Diameter: 3 cm for both Please allow for some margin of error. Both the long and short ones are from the same brand, so the quality should be the same. These are cores from 50-meter rolls, with a thickness of about 2 mm, making them sturdy and rigid.