According to the International 'Medical Guide for Ships', the following items are recommended for the administration of oxygen.

Recommended Items Quantity per 10 crew
Complete portable oxygen set containing:
1 oxygen cylinder, 2L/200 bar
1 spare oxygen cylinder, 2L/200 bar
1 Pressure regulating unit and flow meter with tubes such that the ship's industrial oxygen can also be used
3 disposable face masks of choice including simple face mask and non-rebreathing mask