High altitudes create a special challenge to oboists. Reeds made at lower altitudes tend to close down at higher altitudes. What we're calling "high altitude cane" measures in the 9.5-10 mm diameter which will naturally make reeds with bigger openings. This size is especially useful for oboists living or playing at higher altitudes, such as for certain music festivals. The smaller diameter should yield reeds that stay open at the tip more easily. This cane may also be good for more arid climates with some elevation challenge.