Yeah, thanks, that's what I'm currently using. I've got a few years of use out of it, which isn't bad, but it has reached the point where it won't stay in adjustment. A gust of wind can turn it, and it jiggles loose and starts flopping around. Easy enough to fix (reach up and squeeze it together again) but if I'm riding in traffic and suddenly my mirror isn't where I need it, it's useless. I need the thing to stay in adjustment. I have to replace it soon, and would prefer something better.
Is it coming loose at the attachment point to the helmet? Or the 2-dof hinge at the mirror? Sometimes my clip for the helmet visor is not too strong, because the middle prong has made a deep indent in the visor plastic, so I put the clip on the 'other' way, with the outer prongs and the middle prong all switching to the other side of the plastic. That way the curve helps stiffen the connection. Also additionally secure with a twist-tie, twisting extra to cinch it all up.