This 1.25" premium diagonal is the perfect companion for your Founder Optics refractor telescope, or any other telescope. 

The dielectric mirror coatings offer an astounding 99.99% reflectivity which provides the highest level of contrast and resolution during critical planetary, lunar and binary star observations.

Its twist lock compressing ring locking mechanism delivers unrivalled stability while providing convenience and the insurance of not dropping screws during eyepieces changes or snapping them.

The 1.25" nosepiece is threaded for filters. 

 A top notch diagonal, extremely well built.