Festival Ball Mortar Tubes for consumer fireworks (1.4G). These are 1.91 ID x 11-3/4 inches (nominal)long with wooden plug in bottom, they will be black or orange. Use these for consumer festival ball shells (reloadables) which are 1.75-1.90 inches in outside diameter. IMPORTANT: If your shells are smaller than 1.75", use TU2100 spiral cardboard tubes. Firing too small a shell from too large a tube can cause a low-break. Low breaks can cause personal injury or fires being started.