SmallRig Articulating Arm with Dual Ball Heads (1 4" 20 Screws) 18TB There is also a bubble There is also a bubble level built in to see if the camera is straight As the course progresses the lighting environments we explore become more complex giving students the opportunity to expand their understanding of light alowing them to problem solve effectively in any lighting environment The SmallRig Articulating Arm with Dual Ball Heads (1 4" 20 Screws) is designed to enable you to mount an accessory to your camera cage or rig at almost any angle You will also find rubber padding on both ends to prevent damage to accessories and prevent twisting