This is Knobbles and Bobbles' pair of grey crackle glazed ceramic mortice knobs, they are definitely a brown grey rather than a black grey - ask me for extra pictures if that would help! The diameter of these knobs is 6cm and they are supplied with the metal connecting rod needed to join the knobs through a mortice mechanism. If you have any questions, please contact us at info@knobblesandbobbles.com.
These are not compatible with rim locks, sorry.