Lanyards are generally used to attach things together such as your id card, badge holder etc. And the hook is commonly found on lanyards for attaching the latter with the slotted id card. Hooks for lanyard comes in different types, like dog hook, fish hook, wire hook, England hook etc. All these hooks can be used with different sizes of lanyards, be it 12mm, 16mm or 20mm lanyards. As you already know what suits you the best so just select from the items given and choose your combinations to get the price.