Rib hooks are used to tie down canopies on rib /  inflatables. The hook attaches onto the rub strip around a rib. 

Plastic
Marine grade
Hole centre 7.5mm
Width 39mm
To be attached with shock cord, the hook grabs onto the rub strip around an inflatable. 
Some inflatables are smooth make sure the rub strip is pointed down for these to work