There are two ways in which you can do this. The first is separate, where you weigh the item on a scale, and then enter in the weight manually.
The second is when you connect your scale to Cashcow! and do it automatically.
In both of these cases, the item in question must be configured as a scale item.
To configure an item as a scale item, from Stock Control double click on the item in question and then select the Preferences tab from the top of the screen. Tick the tickbox highlighted below:
Once the above tickbox is checked, then every time you put that item into a transaction you will see a popup appear where you can input the weight of the item.
Alternatively, if your scale is interfaced with Cashcow! then the weight will be applied to the item automatically.
Manual or Interfaced
By default, the manual option is used for scale items. If you want to interface your scale however, please see the relevant article under Hardware Setup of this guide.
Scale Range
The scale range can be used to limit the quantities sold. If this option is enabled, then the item will only be put into the transaction if the weight of that item is within the threshold specified.