32 Inch 4% Transmission Flat

The 32-inch aperture is genuinely massive, and the 4% reflectivity makes alignment work straightforward—I was able to get clean fringes within an hour of unboxing. It arrived well-packed, and the 1/8 wave surface has held up through a full day of testing.

Bought this to check the figure on a 12-inch mirror and the 1/8 wave surface is genuinely smooth across the whole aperture. The 4% reflectivity gives nice clean fringes without washing out the view. Arrived well packed in a wooden case with no edge chips.

I use this as a transmission flat for checking my interferometer setups, and the 4% reflectivity gives me exactly the faint return I need without washing out the fringes. The 1/8 wave surface looks clean under test, and the 32 inch aperture covers my whole beam in one pass.