High Park Lock - The locksmith in High Park: Double-Sided Deadbolts - A love story
Door Knobs Communicating : Ball Entry Door Knob Keyed On Both Sides : Double Locking Cylinders : Bump Resistant & Anti-Pick Pins : Automatic Latching : Keyed Alike - Amazon.com
Key-Locking Cylinder w/ Pair of Keys, Double Sided (FORT)) - MBA USA, Inc.
LOKKLATCH D&D Black Two-Sided Key-Lockable General Purpose Gate Latch 50110 - The Home Depot
Pocket Door Lock with Key, Contemporary Entry Square Sliding Barn Door Lock Latch, Recessed 2 Sided, 2 3/8" Backset, Invisible Hardware for 1 3/8” to 2 3/16” Thickness Door (Brushed Nickel) - Walmart.com