This is the Markins bi-directional PG-34N camera plate.
With small radius flange. For round type bodies.
Nikon D3100, D7100, D7000, D90, D80, D70, D70s, D100
Nikon F4, F4s, F6, F100, N90, N90s, N8008, N8008s
Canon EOS 1n / 1v / 5 / 55 / 5D / 10D / 20D / 60D / D30 / D60 / 300D
And others, like Pentax K10D / K20D / Z-1P / ZX-D
Its anti-twist flange effectively prevents any pivoting between plate and camera body.
International standard dove-tail plate, made of highest quality duraluminum, it is light-weight, has a low-profile, and is strong enough to support your camera and lens system.
Dimensions: 52W×46L×13H mm
Weight: 1.1 oz (30 grams)