B+W 102 ND 4X F-Pro (82mm) Filter Type_Close-Up It's a feature

It's a feature

but there's an electronic diaphragm in there for full compatibility with EF mount cameras

not the kind of stuff that has you wondering whether it's legal to call it leather

The Canon Macro Twin Lite MT-24EX is a versatile macro lighting system with a lens-mounted ring and a pair of compact flash units that can be placed freely along their ring segment and tilted independently

B+W 102 ND 4X F-Pro (82mm) Filter Type_Close-Up It's a featureThe B+W 102 ND 4X F Pro is a high quality neutral density filter with 2 stops of neutral density. For lenses with a 82mm thread size. Image is for illustrative purposes only. Actual item may differ.