Apple’s new Mac Pro has been available in a standard desktop tower configuration since December, but starting today, Apple is selling its promised rack model that’s designed to be mounted in server rack setups — starting at $6,499, an extra $500 over the regular model.

From a specification perspective, the new rack Mac Pro is virtually identically to the tower model. Apple offers the same configuration options at the same prices (down to the included mouse and keyboard, which are unusual to see for rack-mounted hardware) with three main differences.

Virtually identical to the tower model

The first is the different case, although both feature the same “cheese grater”-style vents and aluminum handles. The second is the $500 premium Apple charges for the rack model compared to the tower model — with all other specs being equal, the rack model will still cost more, with the maximum configuration being the most expensive computer Apple has ever sold at $53,899. And lastly, there’s no option to add Apple’s infamous $400 wheels, seeing as the rack Mac Pro obviously can’t take advantage of them.

The rack-mounted Mac Pro also includes a set of rack-mounting rails (which Apple notes ship in a separate box), which might explain the $500 premium that Apple’s charging here.

The new rack Mac Pro is available to order now from Apple’s website, with shipping starting in early February.