The sensors in our dash cams are sensitive to the near Infra-Red spectrum as well as the visible spectrum. IR starts at 700 nm (nanometers or nanometre) and for photography extends to about 1,000 nm. (1,000 nm is one micron.) Longer wavelength IR used in systems to see heat levels as in thermal imaging cameras like the Flir are between 1 - 10 microns or 1,000 to 10,000 nm. For our purposes we are concerned with "near infra-red" of approximately 700 nm to 1000 nm or thereabouts. (That's essentially what we want to block with the standard IR cut filters that come on dash cam lenses.)
Certain aspects of the near infra-red spectrum are of interest to photography hobbyists and for scientific purposes and for those purposes various glass or dichroic filters are available that can pass or block specific parts of the near infra-red spectrum to achieve specific effects. That is probably why he is asking the question. Then again, he might also have asked "how far you want to go?" because perhaps you might want a lens capable of being used on a thermal imaging camera which works well beyond the near infra-red part of the spectrum.
For photography purposes you can read all about this kind of thing at
LifePixel.com and see
some examples of what various IR filters can do. Some of these IR filter effects can also be mimicked in Photoshop as explained on that site. With a camera that allows you to access and manipulate the entire
RGB 0-255, 8 bit color pallete such as the Mobius you can make various color corrections directly in-camera as I did with the varifocal IR lens I installed in one of my cams and that I demonstrate in
my thread about that project.
Edmund Scientific (along with
Edmund Optics) is a scientific supply house and it sounds like the technician is a geek who is trying to offer you the expertise he usually offers to students, professors, scientists, experimenters and industry who usually turn to a place like that for their needs. He probably doesn't "get" that you are asking for a normal IR corrected lens for normal video capture.
I guess to answer his question you just need to say that you want to shoot normal video with the entire near infra-red spectrum blocked.
On the other hand, Edmund might not be the best place to find what you are looking for.