The FBH400-40 from Thorlabs Inc is a Optical Filter with Wavelength 400 to 1064 nm, Center Wavelength(CWL) 400 nm, Bandwidth (FWHM) 40 nm, Blocking Wavelength 200 to 1200 nm, Filter Diameter 25 mm (1.25 Inch). More details for FBH400-40 can be seen below.