Thin Wall Latex Sacs

Latex sacs that are thinner than regular latex sacs.  Recommended by some for Sheaffer Pneumonic pens because they are more collapsible.  (Pentooling prefers regular sacs for these pens. We find regular sacs hold more ink). The choice is yours to make. TW14 SAC: Size 14 for Std. Sized Snorkels TW15.5 SAC: Size 15 1/2 for Touchdowns. We do not recommend using thin wall sacs in Touchdowns. The pen will take in 18% more ink with a regular size 15 straight sac instead. TW17.5 SAC: Size 17 1/2 for PFMs; note: we do not recommend the thin wall sacs for PFMs. You'll get an average of 3 times more ink taken in with a standard latex size 17 sac. The thin walls falter when trying to expand and suck in ink.