Ratchet mechanisms allow for placement and blade movement along the rings.
Fixed Ratchet Mechanism - Allows extemsion or retraction along the horizontal axis at 2mm intervals.
Tilt Ratchet Mechanism - Allows extension or retraction along horizontal axis at 2mm intervals and allows vertical movement of retractor blade with a second ratchet.
|Fixed Ratchet Mechanism|
|Tilt Ratchet Mechanism|