Make sentences as in example. Use the correct form of the verbs.
  Equipment                       Function
1. demand valve      --->    control the flow of oxygen to the diver (for)
2. cylinders            --->     store oxygen under high pressure (used to)
3. contents gauge   --->     indicate the amount of oxygen in the cylinders (present simple)
4. cylinders            --->     transport oxygen with the diver (used for)
5. depth gauge       --->     indicate the depth of the water (designed to)
6. buoyancy jacket --->     support the diver in the water (for)
7. diving mask        --->     allow diver to see clearly under water (designed to)
8. contents gauge   --->     a kind of alarm clock for the diver (act as)
9. demand valve      --->     supply oxygen to the diver when he or she needs it (present                                                                                                                      simply) 
10. buoyancy jacket--->     a very strong lifejacket (act as)

Example: 1. The demand valve is for controlling the flow of oxygen to the diver.