Variation

Ratchet type:
Setting by only inserting strap into carrier

Bolt Type:
Setting by fixing strap on carrier with bolt and nut.
Carrier

Rachet Type Carrier

Bolt Type Carrier
Strap

Rachet Type

Single Pin

Dual Pin Type
Snap Idler is a component to keep chain tensioned. It's engineering plastic made "carrier" hold link plates to prevent chain loosened. As shown in below, there are two types, ratchet type and bolt type.

Ratchet type:
Setting by only inserting strap into carrier

Bolt Type:
Setting by fixing strap on carrier with bolt and nut.

Rachet Type Carrier

Bolt Type Carrier

Rachet Type

Single Pin

Dual Pin Type