When tested by hand, both ends ratcheting fine, and the flex action is smooth and has stiffness.
Matco Tools 9GRBLM12 Metric 12mm Double Box End Ratcheting Wrench - Spline Drive
NEW SK Tools USA 88912 Metric 12mm Flex Head Combination Wrench, 12 Point (NOS)
4 PCS Stud Puller Wrench Metric 12MM 10MM 8MM 6MM Used Good Condition
MAC Tools EXPERT E110905 Metric 12mm Ratcheting Flex Head Combination Wrench
Snap on IPLM12B 1/2" Drive 6 Point Metric 12mm Swivel Impact Socket USA
Snap-on Tools NEW 3/8" Drive 6pt Metric 12mm SEMI-DEEP Impact Socket IMFMS12
