Add-ons and Upgrades for Rack Purchases Ventilation Slots in Cabinet Top, Bottom, or Sides from $4.00 Rear-mounted Rack Rails from $20.00 Rack Screws with Washers - 10-32 Threaded for 19" Rack Rails from $3.00 Rack Shelf - Vented from $20.00 Square-hole Rails on Front from $10.00 Cage Nuts and Screws for Square-hole Rails from $3.00 Vented Rack Panels from $12.00 Blank Rack Panels from $12.00 Matching Wood Vent Panels from $40.00 Adjustable Leveling Feet $20.00 Matching Wood Filler Panels from $25.00 Locking Caster Wheels from $65.00