Kaba Simplex 91926D Auxiliary Lock with Thumbturn; Deadlocking Spring Latch with Latch Holdback forKaba Simplex 91926D Auxiliary Lock with Thumbturn; Deadlocking Spring Latch with Latch Holdback for 1 3 4" to 2 1 8" Door Satin Chrome Finish Mechanical Pushbutton Lock Eliminates Problems and Costs Associated with Issuing, Controlling and Collecting Keys and Cards Provides Fully Mechanical Access Control at All Times While Allowing Free Egress At All Times By Interior Thumbturn Deadbolt Models Must Be Manually Relocked; Spring Latch Models