Extra information
M=Magnetic = Y=Yes or N=No
T= Flange Thickness
OT = Optic thickness
WR: Weld Ring
TT = Tantalum
NM = Niobium
K = Kovar
AR= Anti Reflective Coating, Single layer 1x QWOT coating both sides
V = More complex multi-layer dielectric coatings enable a wide variety of tailored transmission / ref characteristics giving for example virtually zero ref at a single design wavelength (V coating) or at two wavelengths (W coating), or over a wide band BBAR or a neutral density attenuation, and many others.
Also available on KF and ISO Flanges