This dialog shows you all these product names and lets you scroll up and down the list in order to pick the product to update or display.
New button lets you set up another product. There is no practical limit to the number of products you can specify.
Delete button deletes the highlighted product. Changes are not effective until the OK button is clicked.
Product Name
This name is used in invoicing to create each line item. The default values below are automatically used to build the line item.
You can subsequently analyse all invoices containing each product
Description
Enter the standard description for this product. The description can be overridden in individual invoices.
Unit Price
Enter the standard unit price for this product. In the invoice line item, the unit price is multiplied by the quantity to calculate the line item total. (VAT and discount is also taken into account)
The unit price can be overridden in individual invoices.
Price Inc VAT
Check this box if you want to specify a product price inclusive of VAT.
When creating an invoice, the net of VAT price shown will be calculated by deducting the calculated VAT from the gross Price Inc VAT.
Per Qty
Enter the default quantity. You will normally expect to override this quantity in each invoice line item.
Product Type
If you specify a category, all invoices issued to this customer will be include in subsequent analysis of the customer type.
VAT rate
Enter the VAT rate applicable to the product. You can override the VAT rate in the invoice line item. Also, the VAT rate will be ignored if the invoice is checked as being VAT free.
Enter the Revenue account to be credited with the value of sales of this product
This product list can be used for subsequent sales analysis by clicking the appropriate tab 
in the Invoiced Items window.