The Apollo 13 survival rucksack #1 included netting designed to protect the astronauts from mosquitos and other small insects in the event that they had to make an emergency landing or mission abort in a tropical climate.
The rucksack with the netting inside was transferred to the Smithsonian by NASA in 1979.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.