Assorted sac kit for the pen repairman. Kit includes one each of latex sacs 12, 14, 16, 18, and 20. This kit will encompass 90% of all pens you come across and are the most often used sizes.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. Sorry, no substitutions.