The knobs below will fit all versions of the Orion Optics GX250 and Europa 250 secondary. Price is for a complete set of knobs.
A. Knobs for Orion Optics GX250 and Europa 250 Secondary
Part: GXsec
Fits: Orion (UK) GX250 and Europa 250 secondary
Knobs: Black plastic, 19 mm (3/4”) diameter
Threads: Stainless steel
$25.95