Mortise lock replacement

I spoke to you over the phone today, and am sending you some pictures of the door to deck that I need to reorder. I just need the guts of the door latch (you had mentioned it started with the letter (m)... sorry, I forgot the name of it. The distance between the two mounting screws is 4 inches. Thank you for all your help with this. Image 7598 is what I need to order. If you can provide me with the cost of this item so that I can get it ordered and the details of ordering it that would be great. Thank you for everything. Luci