What CAN you say about amp feet? I can say the sphinx glides are the only way to go! Over the years, I have drug or worn off more rubber feet than I care to remember. These feet offer the cushioning of rubber feet with the durability of metal ones. You can drag your speakers over rough concrete, gravel-you name it, with no damage to your equipment & no forcibly removed feet. I would encourage anyone moving their equipment regularly to put these on ALL your speakers, amps-everything that will ever sit on the floor. They are a cheap investment that will increase the durability & longevity of your equipment. You can drag these sphinx glides over rough concrete, gravel, whatever & they take it all in stride. Plus, they hold your amp up away from the previously mentioned rough concrete, gravel, etc. so you avoid wear & damage to your amp. As an added bonus, these are rubber backed, so you get the cushioning of ruber feet with the durability of metal ones. Very durable. Lots cheaper than re-tolexing your speakers, or worse, replacing them.
Have you ever set up your amp to notice it was a bit wobbly? Then notice you've somehow ripped off one of the rubber feet? While you can still rip these off it's a lot harder. They have a metal cap over the rubber that helps prevent damage. Very cool and inexpensive upgrade.