Acapela is... a-cape-for-Bela, and a box.
It is composed of two things, a circuit board and a box (or enclosure). The circuit board has space for eight potentiometers and two 1/8" TRS (a.k.a. mini-jack) connectors for stereo audio input/output. It attaches directly on top of Bela. The box just keeps everything together and makes it easier to move around.