The 100-175Q SIS unit is an upgraded version of the 100-175 SIS unit.

• SIS yellow/blue box stays the same as 100-175.
• The older 100-175 internal PCB's (x2) have been replaced by 1 PCB.
• Silent operation. The 100-175Q PCB switches electronically, so no clicking of relays
• Wiring has been simplified as the 0v does not need to looped.
• The 100-175Q PCB fits existing 100-175 units.
• All rail and shaft mounting are the same as 100-175Q SIS system. See 100-175 for diagrams.