The PURE TUBE absorbers are specifically designed for Tube Amplifiers and now are also available with screw threads in a set of 4.  If you want to completely replace your existing feet, just specify the thread size* you require on your order. If the screw option is selected the four feet come shipped with two sets of 4 x M8 screws of lengths 25 and 35mm.  Ideally you should just rest the equipment on them to take full advantage of the cork absorption.
The new PURE range has a gel pad on the underside and an air cell between the two aluminium layers to provide an additional pneumatic damping effect.
Possible configurations:
With the cork side under the feet of the device
Positioned directly under the equipment base
Existing Feet replaced with the screwable version
For Solid State Amplifiers try the MASTER series instead.
The heavy duty, high voltage transformers of Tube Amplifiers produce mechanical vibrations which disturb the flow of signals within the internal boards, cables, electronic components and especially the sensitive tubes. An additional "floating" aluminum inlay called "HS-plugin" is used for horizontal stabilisation.
bFly's 4TUBE absorbers demonstrably make the sound more relaxed, spacial and natural.
Foot Dimensions: Height 21mm  Diameter 44mm