This is the Dubro Micro Servo Mount.
Lightweight durable ABS plastic mounts work with any brand micro servo. Mounts two micro servos to foam, wood and other materials.
Length of Mount : 1.2 in. (31 mm)
Servo Mounting Area Length : 0.39 in. (10 mm)
Servo Mounting Area Width : 0.25 in. (6.2 mm)