4U [270mm H] 6U [368mm H] 9U [500mm H] 12U [634mm H] 15U [769mm H] 18U [1 mt H] 22U [1.2 mt H] 27U [1.4 mt H]. Standard 600 wide and 450mm deep. In the last few years prices of server racks have been high, but Rack Supplier has succeeded in reducing their prices while maintaining very high quality.
eBay