This OConnor Bellows Ring is a 150-114mm threaded ring that reduces the opening of an OConnor O-Box WM, enabling you to use lenses with a 114mm outer diameter. A threaded retaining ring supports mounting 138mm round filters..

• For OConnor O-Box WM Matte Box
• For Lenses with 114mm Outer Lens Barrel
• Accepts 138mm Round Filters