This curve planer has a spring steel base that can be flexed to cut both concave and convex surfaces and also works as a flat planer. It has a cutting width of 3 5/32" and a min. concave radius of 18" and a min. convex radius of 16". Comes with a powerful 700 watt motor with a no-load speed of 16,500 rpm's and weighs only 7 lbs. Ideal for stairs, boats, barrels, furniture, posts and all kind of custom work.