The Lamy T51 bottled ink features a stable, wide bottomed jar that helps stop tipping and prevent spills. The bottle's interior is cone shaped, forming a collecting basin or well, which assists in getting more ink out of the bottle and into the pen. Plus, there is the thoughtful addition of roll of blotter tape in the base of the bottle to clean the pen after filling, or to blot writing.
Lamy T51 bottled ink in Blue specifications: