The PO-ZWP-L4-800-12-AR from ALPHALAS is a Waveplate with Wavelength Range 400 to 820 nm, Waveplate Thickness 2 mm, Waveplate Diameter(Inch) 0.4 Inch, Waveplate Diameter(mm) 11 mm(Clear Aperture). More details for PO-ZWP-L4-800-12-AR can be seen below.