The user can add items to the normal sale using the speed key window. If speed keys are set at the CAS Level, the speed key will not push to the POS unless the item is in the POS, with the exception of service items (these do not require quantity on hand to be a speed key).
The user is allowed to configure 24 keys in the speed key settings page in configuration menu. When the user clicks on a speed key he will be taken back to the transaction sale screen with that item up on the screen and ready to be purchased. Here are detailed instructions on how to set your Speed Keys on POS and also to set them up on CAS.
You may add items as speed keys that have been manually added to the Master Item through the UI, you can also sell those items without importing them to the store. The downside to this will be your inventory for these items will show in the negative. - Read more about Items with Negative Quantity.