Match the job
Single wall is the everyday board. Double wall, made in the UK, is the stronger board for heavy or fragile goods, and it is the board removal cartons use. A crash lock is a style: the base opens into shape and a peel-and-seal strip closes it.
Wholesale Cartons does not treat those as substitutes. An Amazon inbound carton follows the Amazon list. A house move follows the removal cubes. A posted order follows the postal or crash lock list.
Size still comes first
Measure the goods. A double wall carton that is far too big still needs fill and still lets the goods move. Orders by 3pm leave that day.