They are key operated from the outside and lever handle operated from the inside. The latch automatically deadlocks on closing the door and the snib function (bolt hold back button) enables the latch to be held back.
eBay
Backset: 40mm. Yale 723 Traditional Nightlatch with narrow style and a snib function which enables the latch to be held back or deadlocked internally. Inside handle can be deadlocked by a reverse turn of the key in the outside cylinder after closing the door.
eBay
The latch can be deadlocked by the snib button internally and the snib function enables the latch to be held back. This nightlatch is suitable for both left and right handed, inward opening doors and is supplied with the Yale 1109 cylinder and 2 Keys supplied (Key blank: B-KEY-1109).
eBay
3* Star Yale Euro Cylinder Door Lock AS Platinum TS007 Anti Snap High Security
eBay
Old stock never been used just the packaging a bit damaged and gone yellow
eBay
eBay
The latch can be deadlocked by the snib button internally and the snib function enables the latch to be held back. This nightlatch is suitable for both left and right handed, inward opening doors and is supplied with the Yale 1109 cylinder and 2 Keys supplied (Key blank: B-KEY-1109).
eBay
Yale deadlocking nightlatch. P85 Deadlock Narrow Nightlatch. We specialise in all things DIY. Rest assured this is a genuine Yale product. The centre of the keyhole must be 40mm from the edge of the door.
eBay