Ultra Feet by Bassocontinuo are an enhanced isolation system for use with almost any component. Prices are for a set of four and the different levels accomodate different componet weights.
The Level 1 Green feet are a general purpose entry level foot that will support a wide range of components from .3kg right up to 60kg.
The Level 2 Silver feet are much better for lighter components up to a maximum of 10kg.
Level 3 Red feet are designed for components from 7.8kg upwards to 15kg
Our website page on Bassocintinuo will tell you more :-)