Using waterproof packaging and adding plastic film to prevent moisture and water. Or according to your needs.
The inner size of container is below: 20ft GP: 5.8m(length) x 2.13m(width) x 2.18m(high) about 24-26CBM 40ft GP: 11.8m(length) x 2.13m(width) x 2.18m(high) about 54CBM 40ft HG: 11.8m(length) x 2.13m(width) x 2.72m(high) about 68CBM