Old packages of sheet protectors have codes on them, usually with 119 because that stands for the size 11" x 9". Here is more information:
SP119 = Sheet Protector 11”x 9” - these were vinyl, so close to Avery 73900 https://www.avery.com/products/sheetprotectors/73900
PV119G-50 = Poly Vue 11”x 9”, Non-Glare, 50 count, choose from the new non-glare in Heavyweight or Super Heavyweight https://www.avery.com/products/sheetprotectors?filters=clarity_Non-Glare
QL119 = Quick Load, which now are available in Diamond Clear or Non-Glare https://www.avery.com/srch?q=quick-load