RECORD CLAMPS: AN ESSENTIAL DEVICE TO OPTIMIZE THE PLAYBACK OF YOUR FAVORITE VINYL ALBUMS.
Both models have the same weight: 0.5 lb. That is because 0.5lb is the threshold point from which 2 effects are evident:
1) Platter and vinyl pairing are reached
2) Vibration damping. Adding more weight, according to our tests, is redundant: The effect is the same and the additional weight, in the long term, will produce premature wear. 
- Minimizes vinyl pressing problems. 
In the case of the TWISTER II model (with which we may want to make up for some slight pressing defects), the greater pressure is achieved through a simple inner seal that "catches" the spindle, not with additional weight.
 
The best record  clamp  for you will depend on your listening habits too: if you choose the WEIGHT MODEL you will be able to install and uninstall it with the platter spinning (on the fly). In case you choose the TWISTER II MODEL, you will need to stop the turntable motor to install and uninstall it. 
The TWISTER II model doesn't need to be threaded to act thanks to its inner seal interaction with the sub platter spindle.
By the way, the TWISTER II model doesn't need to be threaded to act: it has an inner seal to work together with the sub platter spindle.
Machined in solid 6061 Aluminum, Maximum diameter 85 mm, Weight: 0.5 LB approx.
Elegant finish.
Revolutionary butyl decoupling stage situated in the clamp's lower surface. It also prevents slides and helps protecting the label.
 
Safe handling, good hand grip.
BOTH MODELS ARE SPECIALLY DESIGNED TO BE USED WITH REGA TURNTABLES AND WITH GREAT COMPATIBILITY WITH MANY OTHER TURNTABLE BRANDS.
COMPATIBLE WITH REGULAR HOLE AND LARGE HOLE (45 RPM VINYLS).