Fotga Matte Box Lens Cloth Donut Knicker for DP500III - Durable Camera Accessory for Cinematic Filmmaking & Photography - Perfect for DSLR, Mirrorless & Video Cameras

I bought this as a solution to the donuts on my DP3000 Matte Box. It fits around the DP3000, but be warned: Everything about this is tight. I could barely fudge this around a lens with a 72mm front filter diameter (I don't think its physically possible to fit it around anything wider than that). You might even be better off cutting the elastic with scissors and inserting a small rope inside for controllable tension.If you are thinking about changing lenses quickly, forget about it. I often have to attach it to the lens first and then monkey it around on to the matte box (which is almost as hard on your fingers).