It means that you will need to use the key to unlock the door no matter which side you are on.
Single vs double cylinder door lock.
The difference is that you need to lock the door from both inside and outside with the key.
A thumb turn opens it from the inside.
Double cylinder door locks.
Double cylinder locks contain two cylinders.
Instead the door is locked or unlocked using a thumb turn style lever.
These locks require a key to lock or unlock the door both from the outside and the inside making them a little safer in one regard.
A double cylinder deadbolt has no thumb turn.
This term generally refers to the deadbolt section of a handle set or to the individual deadbolt itself.
The number of cylinders inside a lock translates to the number of keyed entries on the door.
The single cylinder deadbolt is the most common.
Double cylinder locks is the number of cylinders.
The primary difference between single cylinder vs.
A simple thumb turn locks and unlocks the door.
A double cylinder lock also has a key on the inside which is required to operate the deadbolt.
It is found on front or back exterior doors and requires a key to open it from outside.
Single cylinder locks are usually less costly to purchase and install than double cylinders.
While the single cylinder deadbolt only features a locking mechanism requiring a key on one side the double cylinder deadbolt has it on both.
On the other hand single sided deadbolts require key to unlock from the outside only.
This prevents intruders from entering and exiting easily.
Single cylinder deadbolts and handlesets are operated with a key from the outside but do not require a key for locking or unlocking from the interior of the property.
A single cylinder has a keyed entry on one side while a double cylinder has keyed entries on both sides.
This is the main difference between these two types of deadbolts.
Instead the door is unlocked with a thumbturn style lever.
This difference has one primary trade off.
Double cylinder deadbolts entry knobs and handlesets require a key for locking and unlocking from both the exterior and the interior of the property.
They are also more convenient since there s no need for a key to operate the lock from the inside.
Doors outfitted with single cylinders are unlocked with a key from the outside but do not require a key for unlocking from the interior of the property.
All deadbolts have a key on the exterior side for security.
Double cylinder deadbolts are locks that require a key to open from both the inside and outside.
Just like single door locks you will also require to use the key to lock the door.
Double cylinder deadbolts or handlesets require a key for locking and unlocking from both the exterior and the interior of the property.
Single sided deadbolts have a knob on the inside that is used to unlock and lock them from the inside.
