This is a 33066FL01-330R Float Glass Plane Ruled Diffraction Grating, sourced from the reputable vendor MKS/Newport. The grating, which is 12.5 x 25 x 6 mm in dimension, is a Blazed Ruled Reflective Grating with a Sub Type of Rectangular.
The grating's physical data includes 1200 grooves per millimeter, a blaze wavelength of 400 nm, and a blaze angle of 14 degrees. The orientation vector is set at x=1, y=0, z=0, and it operates at the first order. The grating side is the front, and it is coated with nwr 53-330r-1264-1p.
The material ID is soda lime ru clear, and the grating is designed to work optimally with a wavelength of 588 nm. The grating's web links are valid and lead to the product page on the vendor's website, indicating that the item is in stock.