Description The large o-ring is used for all Sheaffer "Fat" Touchdown (first year) or PFM barrel seals. This O-ring can also be used for converting pens to eye dropper fillers. Quantity discounted based on how many you need.Products by Snorkel Solutions, an entity owned in full by Anderson Pens, are available for sale to end-user customers only. These products may not be bought for re-sale, either as a single product or coupled with others as a kit. Consequently, Anderson Pens reserves the right to refuse orders placed by customers who breach this condition or if Anderson Pens reasonably suspects, at its sole discretion, a customer has breached, or intends to breach this stipulation.