Super containers are 24 TEU
Standard containers are 20 or 40 foot. Shipping and storage capacity are measured based on the 20 TEU. Standard height is 8.5 feet. There are tall containers (9.5 feet) and long ones at 48 feet, Width is 8 feet. There probably are some 24s out there as half 48, but it would be an unusual box for international shipping.