I have never heard of Jas MB. Walked into a Barney one day and found this small ZF bag in black pebble leather and was in love.
It was just right, not too big, not too small. It was not weighty. It has no embellishment. It can be crossbody or shoulder. It is minimum with no logo. It was made in England.
The price point is fantastic for the quality.
The worksmandship is wonderful. Everything was sewn tight and right.
Main compartment can be expanded by lifting up the fold. One small open inside pocket (for phone I guess). One zip compartment on the back outside. Two small toggle compartments on the front (very discreet).
If you are looking for a black bag that's casual but not run of the mill, this is it.