Anyone who sends something is sending two things: the product and the box. In the case of a sample, that box is actually the first thing your customer holds in their hands, and it helps shape their impression of the rest.
The standard version is a tailor-made box made from 1.7 or 3 mm cardboard. We mill and crease the sheet in a single pass, so the fold lines are already in place and the box folds shut without glue. Printed on the outside, or on both sides if the opening mechanism itself is meant to be a feature.
If any samples are to be left in place, then it is a sample box with felt compartments. Each sample has its own place; nothing gets jumbled up, and the felt also cushions the impact of transport.
If the box is intended to last for years in the hands of a sales representative, then we are talking about a steel box made from 4 to 18 mm plywood. It can withstand repeated opening and closing, whereas a cardboard box won’t last a season.