Item types are used to group related items. Examples of item types might be books, CDs, or DVDs.
When adding to your institution's catalog you will create an item of a particular item type.
Importantl: Item types are what you apply circulation rules to. Circulation rules govern how your institution will lend its items: Checkout length, renewal policy, hold policy, etc. For example a circulation rule applied to the DVD item type may enforce a payment of $1.00 for checking out any DVD.