Simplex makes sturdy, secure no-frills locks that simply work. This one needs a cylinder to work. You have to enter the combination correctly to enter.
Buy Simplex 1021S-26D-41 Pushbutton Lock at Amazon
Simplex 1000 Series Pushbutton Lock with Knob. 1021S = Combination Entry and Key Override. Prepped for Schlage large format IC Core (cylinder not included, see “companion items”) Fully mechanical lock, no batteries. Satin Chrome (26D) Finish. … more