bounce box
n.— «Her husband, Bob, brings her items from home when he hikes with her once a month, most recently her sturdier pair of broken-in hiking boots. He also mails her the freeze-dried food packages she assembled months ago. And she has what she calls a “bounce box” that she ships ahead to herself with items she only needs occasionally, such as waterproofing supplies or detailed trail maps for different states.» —“Taking a look inside a long-distance hiker’s backpack” by Debbi Snook Plain Dealer (Cleveland, Ohio) July 15, 2001. (source: Double-Tongued Dictionary)