ZF KIT description of the catalogue:

ZF Kit-Catalog
The Kit Catalog enables you to put your transmission into operation again - in a rapid and uncomplicated manner. The Kits contain all the important parts you need to exchange any part or component and to reassemble your transmission again. You can carry out a complete repair. And usually the entire component is replaced, not only one spare part. That means that, after repair, the quality of your unit is better than only after having exchanged one single part.
Your benefits from using the ZF Repair Kits are as follows:
The kits you receive are always up-to-date.
Daily modifications are taken into account.
Kits can be obtained more rapidly than single parts because they are on stock.
You can be sure to receive the highest quality and the correct kit by using ZF original spare parts which you can recognize by the original ZF packaging.

The online Kit Catalog offers you a simple and uncomplicated possibility to find spare parts. The following criteria will help you to find your kits:
Item numbers
Transmission families
Transmission types
Parts used -> by seeing which parts were used, you can find out which kits contain a spare part and in which transmissions a kit is used