Long Perng Diagonals
Long Perng diagonals provide precision alignment and high reflectivity for improved visual observing performance.
ZWO Seestar S30 Pro Smart Telescope – Automated Astrophotography & Night Sky Imaging
As expected from Pegasus Astro.
I've used one before for camera lenses and wide field imaging. This longer one is for my 90mm triplet refractor. I find Setting 1 works well most of the time, saving a bit of power. You only need to warm things to a fraction above dewpoint to stay dew-free.