Part #ASC-CH1 Offers enhanced water cooling ability for the quartz crystal, and compact design allows this head to fit into small spaces. Fully compatible with INFICON, MAXTEK, SIGMA, SYCON, or Intellemetrics controllers. 5 or 6 MHz crystals can be used. 1/8" (3.175 mm) water lines are 30" (762 mm)long. Use with either ASC-BT1, or ASC-FT1 feedthru.