DTB720

The technical-index table's Maximum Transmissivity column reads '≥50/500±2' in both the original scan and the newer, cleaner re-scan of the booklet (booklet p.106) — this appears to be a genuine typesetting error in the source booklet itself (the Front Cut-off row directly below it also reads '500', suggesting the peak-wavelength digit was accidentally copied from the row below rather than mis-scanned). Per the booklet's own naming rule ('Band-pass filter glass is named DTB, and wavelength of the peak is used as its serial number', booklet p.102), type DTB720 must have λM=720. This is confirmed by the overlay spectrum chart (booklet p.104, 'Spectrum Charateristic Curve Of Band-Pass Filter Glass'), where the tallest/broadest curve is explicitly inline-labeled '720' and peaks at approximately T=54% near λ=720nm, consistent with the DTB720 type code and its documented ≤140nm half-width (the widest of the series). Corrected to ≥50/720±2 accordingly.