Rapid-batten is the name of small assembling angles used to connect battens.
The angles have special arranged drill holes which can be used like a compass. There are drilled holes with distances at 10°, 30°, 45° and 90°.
First you screw the angle with the centre hole on the batten then you can turn the angle into the right position. You can first set the angle and then fix it, or you can first fix it and then read off the angle. So you can easily connect battens precisely and fast.
If you read off the angles afterwards you can transfer them into your CAD program.
So these small angles and battens are a construction kit for prototyping, etc.