The Beseler 23CIII Variable Contrast Lamp House converts your Beseler 23CIII into a multi-contrast enlarger.

Features:

• The specially designed 23CII VC system incorporates a unique
  dual-range design that provides three separate pre-calibrated
  filtration channels covering all popular black andwhite multi
  contrast papers.
  
  
• Solid-state, internally controlled power supply. It requires no
  external transformer, no external power supply, no external
  voltage stabilizer.
  
  
• Continuously variable dial-in contrast grades -0 to +5 and bright,
  white light focusing.
  
  
• Its computer designed exposure control device automatically
  maintains a constant printing speed throughout the entire contrast
  range, eliminating the need to recalculate the exposure when
  changing the contrast.