The M-311 saya will fit all Tojiro Santoku knives up to 180mm please see links below for the knives it fits from the Tojiro range.
Tojiro saya/wooden sheaths are made from magnolia wood which is a hard wood and is very light weight, the says are all different and the picture you see here will vary a lot in colour and wood design. They can be dark and some very light in colour and we cannot guarantee a type or colour.
They have a small wooden pin which you remove to place your knife inside and you can then reattach the pin to make it safe. If you have a knife case you can still get a saya as they prevent the blades coming through the case and give the blade even more protection.
The saya are also very good if keeping knives in draws at home or in the professional kitchen as they will be protected from other sharp blade which can potentially chip or dull the cutting edge.