The knobs below will fit the Mag1 Portaball secondary with three collimation screws. Price is for a complete set of knobs.

A. Knobs for Mag1 Portaball 12" Secondary

Part: PB12sec
Fits: Mag1 Portaball 12" secondary

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel


  1. Knobs are positioned above the secondary spider.
  2. Screw tips are beveled to fit into the secondary mounting plate recesses.