This is a single or double-use vial containing 1.8ml of blue threadlocker.
This is used to secure threaded objects such as bolts or nuts to appliance parts. Namely, the two most popular uses are for transmission bolts going into a washing machines' washplate, and the metal hub tub nut that we sell.
The vial contains enough droplets to handle both items.
Threadlocker is required by the manufacturer to be used on these items when re-installing parts. Otherwise, during operation they may back out of the machine and return to a defective state.