The 24.6-megapixel camera has a 35mm full-frame Bayer sensor, and it weighs just 370g (less than a pound), without the battery and memory card. That's lighter than full-frame cameras like the Panasonic S1 (1,021 grams with the battery and card), Sony A7 (650 grams) and Canon EOS RP (485 grams). Sigma is calling the fp a "pocketable full-frame" camera, and at 112.6 x 69.9 x 45.3 mm (or 4.4 x 2.75 x 1.8 inches), it will likely fit in the palm of your hand.
Sigma hasn't announced when the Sigma fp will be released or how much it will cost, but the company's other mirrorless cameras range from $800 to $1,200. It's too soon to predict how successful the camera will be. If nothing else, it's certainly ambitious.