Becker BK7 or BK9

N-BK7 High Precision Windows bk7 slot Thorlabs' N-BK7 High-Precision Windows are available in Ø12, Ø1, 25 mm x 36 mm, Ø, and Ø2 sizes They are available uncoated for the 350 nm mandiri4d slot I know some out there have Becker knives, some more then a few lol Which is better as a good field knife the BK7 or the BK9

pave slot top trench drains Based on the silver slot-head screws and the diamond Emilia and her Zeiss-bodied sister, the 7x35 Asterette, utilized BK7 prisms