When you create a Work Order, you will be able to indicate its "Severity". The options are Soft Down and Hard Down.

The item is on an Open work order, and the severity of the issue classifies as more significant, such as the need for a new engine. The item will not be able to be rented when it is in a hard down, and it will be flagged with a Red Unavailable sticker.

The item is on an Open work order, and the severity of the issue tends to be minimal, such as the need for an oil change. The item will still be rentable when it is in a soft down.

If you attempt to add an Item that is on a Soft Down Work Order, you will be flagged with a Yellow Available sticker.