This is a great Georgian knitting sheath with many attributes.
Firstly it's probably a Eskdale knitting sheath with the forked shaft which hooks on to  the cow belt, these are quite difficult to come across.
The sheath has an inlaid heart near the top of the shaft.
It  also has an oval window with the name Beth, 1802 behind the glass panel.
There is an inlaid panel to the front of the sheath in contrasting wood to the mahogany.
On the back is a further glass oval panel with some hair in it.
There are also dot inlaid panels in ebony and fruit wood on the back as well.
A great knitting sheath, in good condition and measuring 20cm l.