Reply to inquiry and inability to offer substitute

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!