In the days before the Clone Wars, the Hardcell Class Transport was the cargo king of the space lanes. While running with a skeleton crew of only five sentients, it could carry enough materials to build up a large city. However, loading and unloading the massive cargo bay could require as many as 15 workers at a time.
The Hardcell fell out of favor as newer transports began to include vehicle berths, allowing cargo to be driven on and driven off. Facing faster, more efficient loading methods and lower crew requirements, the Hardcell saw less and less usage over the decades and is now a rare sight on most planets. Even though the Hardcell is better shielded, faster and can carry more cargo than most modern transports, its rarity prevents all but the richest of sentients to purchase and use it.