TEXT: www.games-workshop.com
  APOCALYPSE
  The Silver Towers of Tzeentch form an outlandish sight on
  the battlefield. They appear as clusters of intricately carved
  and fluted towers resting upon a circular island and topped
  with slender minarets of gold or bronze. Each tower is a
  subtly different creation of disturbing beauty, with the fine
  snouts of weird, magically-powered weapons studding
  their walls.
  However, the most disturbing aspect of the Silver Towers is
  that they are not land-locked but drift through the skies
  above the battlefield. Each tower contains dozens of
  Tzeentchian Thrall-wizards who focus their powers to rain
  magical destruction on Tzeentch’s foes. Most potent of all
  are the wardings woven about the towers, so that as they
  advance a wall of magical energy springs up around them,
  protecting both the tower and any followers of Tzeentch
  that are nearby.
  SILVER TOWER OF TZEENTCH
  POINTS: 400
  UNIT: 1 Silver Tower of Tzeentch
  TYPE: Super-heavy Skimmer
  STRUCTURE POINTS: 2
  WEAPONS AND EQUIPMENT: 
  - 1 Turret-mounted Beam of Power
  - D6 Turret-mounted Bolts of Change*
  WEAPON             RANGE
  STR AP
  SPECIAL
  Beam of Power          48”
  D
  2
  Heavy 1, Destroyer
  Primary Weapon
  Bolts of Change*        24”
  8
  1
  Heavy 1, Primary
  Weapon
  SPECIAL RULES:
  Possessed: A Silver Tower of Tzeentch ignores Gun Crew
  Shaken and Driver Stunned results.
  Protective Wards: The Silver Tower is protected by potent
  magical wards. The tower itself and any friendly vehicles
  within 6” of the tower count as obscured. Other friendly units
  in range receive a 4+ cover save. 
  *Bolts of Change: Every time the Tower fires its Bolts of
  Change, roll to see how many shots are fired. Each shot can
  be fired at different targets, if the controlling player wishes.
  Weapon destroyed results affect this weapon differently –
  reduce the number of bolts of change fired by one for each
  Weapon Destroyed result the weapon is suffering.
  ARMOUR
  BS    FRONT   SIDE    REAR 
  4       12         12        12   
  © Games Workshop Limited 2008. Games Workshop, Warhammer, Warhammer 40,000, Apocalypse are ©, TM and/or ® Games Workshop Limited 2008. All rights reserved.
  
SOURCE: textdata/thevault/Warhammer/40k/1st-8th Editions (Prior)/5th Edition (2008)/Apocalypse Datasheets/40k 5e - Chaos Space Marines - Silver Tower of Tzeentch.pdf