Mechanical keyboards are prized for the smooth, precise feel of their key switches. It's all about the tactile experience. The underlying switch mechanism isn't the only component of that equation, though. The key caps also contribute to the overall feel, and Thermaltake and just kicked those up a notch. Instead of sticking with traditional plastic caps, the peripheral maker has introduced a lineup of metal replacements.
The metal caps are crafted from "a zinc alloy" and finished with a UV coating. They're designed to fit Thermaltake's own Cherry MX-based keyboards, but I suspect they'll work with similar models from other manufacturers. Most Cherry MX keyboards have similar caps.
As far as I can tell, the metal caps have solid faces that prevent backlighting from illuminating the key markings. They're likely to be heavier than conventional caps, too, which could make the key response a little lighter. But they also look awesome, and they should feel nicer under one's fingertips.
Thermaltake is offering five-key sets for $19.99 and a 38-key pack for $69.99. The smaller sets cover the Esc key along with the WASD or directional triangles, while the larger one fills out the rest of the alpha and main punctuation keys. Entire Cherry MX-based keyboards are available for same price as the 38-key set, so the metal caps are obviously a premium accessory. Still, I wish Thermaltake had a full, 104-key set—or an all-metal keyboard with a matching body.