I have to defend the Dunlops here...I have had them for 15+ years (yes, one set is that old), I have had Schallers also. Both work great, but I have never seen Dunlops fail. For those of you who like physics, the Dunlop design is just a fool proof as the Schallers. The ball bearings do not support the weight of the instrument when in any normal position, but yes you can pull all you would like on the them at any angle and the don't come out. I do like the profile and operation of the Dunlops better.