ADJ for n
The 'useful' group
These adjectives indicate that something is useful or convenient, or not.
It is the most elegant and comfortable of all the Hong Kong hotels, and is extremely convenient for the airport.
The new device may be useful for car navigation and military surveillance.
With all of these adjectives except usable, the preposition for is sometimes followed by an '-ing' clause.
convenient handy impractical inconvenient invaluable practical usable useful useless valuable
My little knife with a curved blade is also invaluable for preparing food.
They are useless for quenching your thirst and loaded with calories besides.