Noodlers Flex Nib Fountain Pen, Piston Fill, Medeival Lapis - Blue/White/Black you are buying ONE Medeival Lapis Standard Flex Nib Fountain Pen piston-fill mechanism; take any fountain pen bottled ink length closed: 5 1/8"; posted: 5 1/2"; weight: 0.4 oz steel flex nib fine/medium as described by Noodlers ink...ink line width dependent upon nib pressure applied Instructions on how to use a piston fill fountain pen are included from Noodler's Ink