i heard these where not good , it keeps the reed moist, they are supposed to dry out as to retain shape, so i was told anyway, by a pro player….
personally i use the cheap Rico plastic reed holder (4 pack), the farther the reed goes in the flatter the tip gets, the reed holder has a floppy plastic palette that forces the reed tip flat as the body of the reed is inserted, a “teeter totter” effect, worked for years for me and the reed breaths and as the reed dries the tip remains (forced) flat