|Manufacturer||Von Duprin Exit Devices|
Von Duprin 88 Dog Screw. Newer style, after 1975 or so. If you have an older exit device they no longer make that screw. I would recommend the D100, Panic Bar Retainer, for dogging down your device.
Von Duprin 88 dog screw 14 threads per inch
Von Duprin Part # 090083