As with most of these locks setback is 2 3/4. A lock with the key over ride is a must when there in only one entrance/exit. Most are not and it. The item "NOS Kaba Simplex LL1021 Pushbutton Lock Key Over Ride Core Installed withKeys" is in sale since Monday, April 09, 2018. This item is in the category "Business & Industrial\Construction\Building Materials & Supplies\Doors & Fixtures\Locks & Locksets".The seller is "bake98" and is located in Oxford, Pennsylvania. This item can be shipped to United States.