I bought these for a project I never started. Never been mounted or used.
The spider will fit a minimum of 21.5" ID OTA, and with long enough screws, I suspect upwards to a 22.5" ID OTA would accomidate it too. AstroSystems can cut these down to a smaller size if needed. This is a heavy duty spider with tapered vanes from 2.5" at the center to 1" on the ends. The holder is for a 3.1" secondary. I paid $83 + shipping for both and will take $70 and I pay the shipping CONUS via USPS Priority mail. PayPal only - No fees.
-Bulldog in photo not included.