(These are not sliders or gliders that fit into track systems)
These hooks join curtains (with curtain tape) to poles with rings or to sliders or gliders
Plastic hooks eventually after some years do tend to go brittle and snap, so why not consider metal instead
Chances are you need an even number of curtain hooks (if hooking up a pair of curtains) and usually there’s an anchor at each end.
To work out how many hooks you need, be guided by the number of rings on the pole or gliders on the track
price per hook