This “Handy” stepper motor unit works exclusively on the SI-EFS Electronic Focuser System and the Focuser Boss II electronic focuser. The design of this motor housing allows you to still be able to manually turn the focus knob on the focuser by simply turning the over-ride knob on the motor housing. This motor has a built-in temperature thermistor for temperature control through the SI-EFS and the Focuser Boss II digital systems.

• The HSM20 motor unit fits the 2.0″ Feather Touch focusers, MPA Retrofits (Takahashi and TeleVue), and Micro Feather Touch® Telescope Focusers for the SCT scopes.
• The HSM30 motor unit fits the 2.0″ Feather Touch Rack/Pinion focuser, 2.5″ and 3.0″ Feather Touch Rack/Pinion focusers, and the 2.7″ Astro Physics focuser with the Feather Touch Upgrade.
• The HSM35 motor unit fits the 3.5″ Feather Touch Rack/Pinion focuser and the 4.0″ Astro Physics focuser with the Feather Touch Upgrade.