It's a good collar from the stability point of view, also considering the max. focal length which is limited. But as time goes on, the locking mechanism is becoming loose. Almost two years ago I dropped the lens and cracked it in two parts, because I failed to fasten the lock. I'm starting to fear that now it could open on its own.
So I figured out I could just buy a replacement. How much could cost, after all? I thought 70-80 €.
Well... 220 $, indeed: