Herein, monastics, what are the twelve sense-spheres?

They are as follows:

1. The internal eye sense-sphere,
2. the external visible-form sense-sphere,
3. the internal ear sense-sphere,
4. the external sound sense-sphere,
5. the internal nose sense-sphere,
6. the external smell sense-sphere,
7. the internal tongue sense-sphere,
8. the external taste sense-sphere,
9. the internal body sense-sphere,
10. the external tangible sense-sphere,
11. the internal mind sense-sphere,
12. the external thought sense-sphere.

These, monastics, are said to be the twelve sense-spheres.