This is a 2" 90-degree mirror star diagonal for all 2" eyepiece holders. Includes a 1.25" to 2" eyepiece adapter. With end cap and plug. Get the best possible views through your scope with this superb accessory - all-metal (black-painted and anodised aluminium) construction gives the whole unit a lovely quality feel. Excellent mirror quality protective coating - the reflectance efficiency is 98%.