It is mainly used in packiing ink to protect ink not to be deteriorate They have different size for different depth:For 1.0kg ink cans:13.5mm,15mm,17.5mm,20mm,22.5mm,25mm,27mmFor 2.0kg ink cans:12mm,15mm,17.5mm,20mm,22.5mm,25mm,27mmFor 2.5kg ink cans:12mm,15mm,17.5mm,20mm,22.5mm,25mm,27mm,30mm