They also pay for equipment repairs.
They may also work in product evaluation and testing, diagnostics, and equipment repair.
They are involved in such activities as design projects for the developing world, biomedical equipment repair and evaluation, and fundraising activities.
New rules in this issue include critical damage and character death, equipment repair and upkeep between missions.
And equipment repair or replacement means it can take two to four weeks to get a pool fully operational.
Planners keep a separate schedule for equipment repair and cleaning.
A backlog of work orders for equipment repairs has dwindled to fewer than 130, from more than 560 a year ago, they said.
It also provides services relating to equipment repairs, road construction and logistics (terminals).
Other commercial mainstays in Herrera include retail, equipment repair, banking, and domestic service.
The visit to Charleston was for electronic equipment repair.