It is a distance between two bores for handle set prep.
![undefined](https://cdn.livechat-static.com/api/file/kb/file/12590274/0a174741ed-5055d5b6b0fb2af66a21.png)
MORTISE LOCK VS TUBULAR LOCK
![Lock](https://lcdn.doornmore.com/pub/media/wysiwyg/pages/door-preparation/mortise-tabular-lock.jpg)
MORTISE LOCK BORE
![Lock](https://lcdn.doornmore.com/pub/media/wysiwyg/pages/door-preparation/mortise-lock-bore.jpg)
DOUBLE BORE
![Double Bore](https://lcdn.doornmore.com/pub/media/wysiwyg/pages/door-preparation/double-bore.png)
SINGLE BORE
![Lock](https://lcdn.doornmore.com/pub/media/wysiwyg/pages/door-preparation/single-bore.jpg)
It is a distance between two bores for handle set prep.
MORTISE LOCK VS TUBULAR LOCK
MORTISE LOCK BORE
DOUBLE BORE
SINGLE BORE