Description One size 15 latex rubber sac for fountain pen restoration. When a size 16 is too large, but a size 14 is too small. This size 15 sac also fits slender 2-4 sized Conklin Crescent, Sheaffer 3-25, and long slender 5-30 and 46 Special pens.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.