Transit cases can be procured in virtually any size to contain something very small to very large which may require several people or a fork lift to move.
Transit cases are usually molded or formed from plastic, composite materials or aluminum so the top and bottom sections are seamless.
The minimum feature set would include: rugged construction to protect the contents from mechanical abuse, tailored internal cushioning, blocking, and bracing, environmental sealing to protect against moisture, humidity, rain, dust, insects, chemicals, etc., multiple draw-down latches to firmly secure the covers on all sides.
Other available features may include the following: hinged or lift-off lid, two removable end caps, pre-cut foam, custom factory-cut foam, or do-it-yourself foam, rackmount rails for installation of 19-inch rackmount equipment, shock mounts for an internal rackmount frame, Retractable handles which are protected in some regard during shipping, airtight seal when the lid is closed and latched down, atmospheric pressure equalization valve , nitrogen filler valve, humidity indicators, wheels or casters, wheels and an extensible handle similar to a pull-around suitcase, legs to allow the removed lid to be used as a desk, and environmental controls: air conditioners, heaters or fans.
The principle design of a transit case is to assure environmental sealing and protection for the contents in adverse circumstances.