Fotga DP500III Pro 15mm Rail 4x4 DSLR Swing-Away Matte Box with Donuts - Compatible with Sony A7R/A7S II/III, A9, GH6, S5II, Canon 5D/6D/7D, R8/R10/R5C, FS7, C300/C500, BMPCC 4K/6K, Ursa Mini, RED - Perfect for DSLR Video & Cinema Camera Filmmaking