Help™ Front Driver Side Windshield Wiper Arm (42647) by Dorman®. Lenght: 23″. Finish: Black. Attachment Method: Spine/Flange Nut. Material: Steel. Wiper End Type: Hook. A streaked windshield isn’t only aggravating, it’s unsafe. If new wiper blades aren’t fixing the problem, your wiper arms may be the culprit. Properly functioning arms are essential to a clear and clean windshield. Count on Dorman to help restore the efficiency of your wiper system and your vision of the road.