Dear

Your letter inquiring about   [subject of inquiry]   was
brought to my attention.

While we manufacture a vast assortment of   [products]  ,
none of our models fit the description which you provided.
We have never manufactured [subject of inquiry].

You may wish to direct an inquiry to the following
distributor, whose firm has been in existence for many
years and who may have the answer you are seeking:

                ____[name of firm]____
                ____[address]_________
                ____[city,state,zip]__

I am sorry that I am unable to be of more assistance to
you.  Best of luck!