The four vane spiders work well for 4 truss type telescopes. This is a special spider, designed to minimize / eliminate  visible diffraction patterns. It is made primarily of aluminum, making it lightweight. The unique center bolt, Spring, and Tensioning Nut, make collimation simple and easy while allowing a large range for adjusting.

 It also features:

• Easy Front Access to Stainless Steel  Collimation Screws
• Allen Wrench for Collimation
• Vanes have Clinch Nuts built in and come with black mounting screws
• Constant tension of diagonal to Collimating Screws
• Light weight aluminum block and vanes 1 1/2 inch tall by 1/16 thick
• This Curved Vane Telescope Spider comes with a secondary holder.
   

Available Options:
Clinch Nut Size	1/4-20 (Default)8-32Two 1/4-20 Chinch Nuts per Vane (+$10.00)Two 8-32 Chinch Nuts per Vane (+$10.00)
Inside Diameter of your tube?
Secondary Mirror Holder size.	For 2 inch or greater Secondary Mirror
Stainless Steel Mounting Screws	(+$5.00)
Upgrades	--None--Dew Heater Vane upgrade (+$35.00)Quick Change Holder (+$35.00)
What is your tube thickness?	<1/2 inch<3/16 inch<3/4inch