Pneumatic servos, unknown manufacture, looks like maybe Brittain Industries

Each Units consist of the following. Assembly components:

Assy no. 1901-163

Assy no. 1901-164

Assy no. 1901-129

Assy no. 1901-3-2

Assy no. 1901-179

Assy no. 3191

Closed length 9"

Extended length 12"