Manfrotto MVH502AH brand_Film Washi Check Nikon's compatibility chart here)

Check Nikon's compatibility chart here)

or several smaller ones

which is not designed to guard your spine- it's meant to provide extra structure- but sort of looks like a spine

The open slot is a factory thing

Manfrotto MVH502AH brand_Film Washi Check Nikon's compatibility chart here)The Manfrotto MVH502 is a sturdy fluid head for video. All metal construction, with adjustable fluid drag on pan and tilt axes. Rated for payloads of up to 10kg, which should accomodate most mid sized video setups. In excellent condition, with minor wear from light use. The base is designed to fit any tripod with a 3 8 threaded fitting (this is a flat base head, not a half ball).