Barograph ink Blue 1 Oz.

This is a Barograph Blue Ink bottle (1oz.). This plastic squeeze bottle comes with crew cap and a spout that is closed and must be snipped, so it can't leak in transit. Only one single drop can last a month. Recorder ink is preferred by some because the traditional metal pen nib leaves a bolder trace that's much easier to read than the very fine trace from the MXFTP cartridge pen.