Perla 4U 600×200×500 Slim Wall Mount Rack Cabinet

A depth of 200 mm is quite shallow for a 4U network cabinet — many network/switch equipment needs greater depth (cables, patch panels, power strips) so manufacturers often design 4U wall-cabinets with depth ~450-600 mm.

The listing you requested (600 × 200 × 500) may be a custom or special variant or possibly a typo in the dimension spec.