Professional grade cinema rings by SimMod. SimRings™ eliminate unwanted lens glare. They allow you standardize to a single 77mm filter size as well as mount into 80mm clamp on adapters for your matte box, sealing out stray light and stabilizing the lens at 2 mount points - the matte box and the camera/lens mount. This means torque created in the gear system won't cause lens movement as you're pulling focus. Not only are SimRings™ functional, but these beautiful rings give a professional touch to your new cine conversion. Combine SimRings with 80mm slip on caps for best results.