I can not figure out how to not display the duplicate entries in a pull down list that displays the cells from a column that has duplicate entries.
The column that the pulldown list pulls its data from contains the names of manufactures, the next column contains the products that manufacturer makes. Some manufacturers have only one product, so only one manufacturer name on one line in the first column. Other companies have multiple products, so there are multiple manufacturer names in the first column over a number of rows. But, as the list is a thousand lines long, I don't want to display any one manufactureer's name more than once, so as to keep the pulldown list as short as possible.

An example:
Pull down menu list.jpg

In this example, if I use Data Validation to make a pulldown menu of entries A1 to A6, I would get the following pulldown list:
Acme
Apex
Bosch
Bosch
Bosch
Digit

So "Bosch" would be displayed three times, but I only want it to display "Bosch" once.
So the desired pull down menu would instead be:

Acme
Apex
Bosch
Digit

I have, as an alternate, tried MERGE & CENTER combining the column A cells that are the same manufacturer's name, but then the pull down menu displays all the blank lines within that merged range of cells, which is even worse.

There is a secondary problem that column A sometimes correctly contains a blank cell, which I would also not like to be displayed in the pulldown list.
Any help on that would be greatly appreciated as well.

Thank you in advance.

...........Carl