First, let's find out how many units of both products are produced daily.

Total units produced daily = Units of product A + Units of product B
                           = 1200 + 800
                           = 2000 units

Now that we know the factory produces 2000 units daily, we can calculate how many units will be produced during the 4-day shipping period.

Units produced in 4 days = Daily production * Shipping duration
                         = 2000 units * 4 days
                         = 8000 units

So, a single shipment will deliver 8000 units of products A and B combined.
A factory produces 1200 units of product A and 800 units of product B every day. If it takes 4 days for a shipment to reach its destination, how many total units will be delivered in a single shipment?