Aluminum alloy and brass spike: with high hardness and density has low harmonic vibration point and high damping; Easy to install, no drilling required, no need to use double-sided tape to avoid damaging the device ADJUSTABLE HEIGHT: The height of the shock-proof foot spikes can be adjusted to fit different types of speakers, amplifiers, CD or DVD players, etc. Isolation Feet: Provides an effective solution to optimize true sound and reduce vibrations in stereo equipment Function: Use Isolation Spike to pause audible feedback from the speaker. Spikes can be installed to separate players, amplifiers, or other audio components from vibrations. The tone be more focused and there be less noise. Each feet can support 8kg / 17.5lbs. Colour:B: Black Material:Aluminum alloy Package Contents: 1 x amplifier foot pad Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.