This Lens support system is perfect for long lenses and is compatible with any industry-standard 15mm rod system, help to create a more stable, vibration-free platform for shooting. The Y shaped long lens support screws onto the 15mm rod clamp to the long telephone lens while shooting. There are two rubber washers to protect the finish off of your lens from wearing. The diameter range of the lenses it works for is, 50mm to 140mm.