Founder Optics 1.25" Dielectric Diagonal Mirror - DIA1.25-M

If you're looking for a nice 1.25" diagonal for your refractor, this model from Founder Optics will do the trick.  The compression ring twists to lock in 1.25" barreled accessories without marring and fiddling with small screws in the dark.  The telescope side slides into 1.25" focusers.  

This Founder Optics 90-degree mirror diagonal has a dielectric coating with over 99.99% reflectivity for bright images.