Universal matte box donut ring cloth donut ring for different lenses Cinematics | eBay
Amazon.com : SmallRig Rubber Donut for Lenses with 58-114 Diameter, with Rear Opening for SmallRig Light Matte Box - 3409 : Electronics
114mm Threaded Donut Rings - Bright Tangerine
Photography and Cinema · MAX-D Matte Box Donut
Movo MB400 MK II Professional Matte Box with Swing-Away Arm. French Flags, Side Wings & Universal Anti-Reflection Donut (for 15mm Rod System) - Walmart.com
Opteka MB-X Pro Metal Matte Box Kit with Universal Lens Donut Set for All Camera Rigs with 15mm Rod Systems - Walmart.com
Black FOTGA Cloth Donut Knicker for JTZ DP30 DP500III Matte Box up to 114mm Lens | eBay