These weight bobbins are perfect for creating a competely weighted warp, or simply weighting selvedge cards. They are hollow and can hold pennies or nickels, nuts and bolts, even gravel to get the exact weight you wish. The top fits securely but is easy to remove. They are 3" (7.3cm) tall and 1.75" (4.2cm) at the widest tapering to 1" (2.4cm) at the narrow center. These are 3D printed in sets of four at the time of order.