These are the same 1.27" W x 1.19" H blue removable dividers used in our 18-Compartment Small Parts Organizer Box, Part No. 4330. Each 4330 case includes a full set of 15 dividers, but we offer replacement dividers in packs of 12 in case you have lost or damaged any. The special "Zerust" material construction helps to ward off corrosion on metal parts in storage. Box sold separately.
We also offer Individual Dividers for 4330 Cases (Part No. 4430-Divider) if you don't need a full dozen.