The W-HPS220 from Ross Optical Industries is a Waveplate with Wavelength Range 980, 1064, 1310, 1480, 1550 nm, Waveplate Thickness 0.04 - 0.09 µm, Waveplate Diameter(Inch) 0.8 Inch, Waveplate Diameter(mm) 20 mm. More details for W-HPS220 can be seen below.