HERE FOR SALE IS AN
ERA Door Lock Cylinder Thumbturn 6 Pin Cylinder 40/40 Brass
40/40 is the size of the lock
40mm (Both Sides) from the centre of the fixing Screw
Please see the 2nd picture - this provides dimensions and installation info
Much Safer than locking your door from the inside with a key
In the event of an emergency and having to evacuate the property there is no time lost searching for the key
Thus possibly saving your life