Where to find LP clamps?


Twenty years ago I remember there were clamps you could put over the spindle to secure/level a LP. I'm considering putting my turntable back into my system and I'm wondering where I can find these clamps if they're still available.

Anyone know where I might find these clamps and/or know if they really make a difference?

Thanks!
jurry
I might argue on that since Michell uses an acrylic platter that I cannot consider it "springy" or unsupported and the clamp realy works best if only applied without locking on the Michell. The same I can say about Oracle tables where you should only slightly screw the clamp to touch the label. Simply saying when you couple a record directly to the platter the minimal clamping is sufficient and best.
M., you are correct in pointing out (as I also referred to in my first post) that the platter/mat situation makes a difference in these regards. In addition, I do think it is possible in some instances, with a soft mat and a thin-vinyl pressing, to 'over-clamp', deforming the record and placing it under stress. Although I doubt that the light weight of the Michell clamp by itself, untightened and acting merely with gravity, could have much of a positive effect (in fact, it could have a deleterious effect if allowed to vibrate), at least we agree that it is a good clamp at a low price.