Seydel Chromatic Standard 48 Key of C
These instruments come without windsafers.
The advantage is the extreme robustness and they are almost maintenance-free.
The airtighness is optimized, however a basic airloss can not totally be avoided.
These instruments offer a reasonable possibility to learn about the Chromatic concept.
They are also good for outdoor activities, because they are not that susceptible to condensation like Chromatics that include windsafers.