Description One size 14 PVC sac. These sacs are designed for use in Sheaffer Snorkel pens. PVC handles modern inks well, without evaporation like silicone sacs. Not recommended for celluloid pens as the PVC can affect the material. The Snorkel's metal sac protector prevents any such issues.Please note: Price is per sac. Pen sacs are measured in 64ths of an inch diameter. Most sacs will need to be trimmed prior to use and are intentionally made longer than necessary.