From the outside, the Karakuri Rasento looks like a broad-bladed, Japanese-style nandao with light, greenish-gray tsuka-ito forming rhombus gaps on the hilt and being gold-colored below (while in the anime having bluish-turquoise tsuka-ito), and which has an orange pair of tufted cords tied to it, as well as a gold kashira, a rectangular gold tsuba, and a saya colored the same as the tsuka-ito (green in the manga, blue in the anime).
Only unsheathed does the sword show what makes it so distinct: it has a plain, single-edged blade with several smaller, blade-like flaps (each with its own wavy temper line) that are attached to one of its sides in diagonal segments. When Sasaki activates the rotating mechanism of his weapon, the flaps open up into a perpendicular position relative to the main blade before they start spinning at high speeds. In this active form, the sword ends up resembling a drill.
The Karakuri Rasento is a powerful weapon while active, since the drilling rotation produced by the sword's mechanisms naturally enhance the strength of Sasaki's attacks. With this weapon, Sasaki was able to overwhelm the General Franky in sword combat and cut its Franken in half.
Sasaki can also use his sword while airborne in half-triceratops form, giving him a method of aerial combat.
Heliceratops (ヘリケラトプス,Herikeratopusu?): While airborne thanks to his propeller frills, Sasaki approaches his enemy from above and uses his Karakuri Rasento to repeatedly slice them with diagonal swings. It was first used against the Gifters of his Armored Division, who had changed sides because of Tama's ability.
Holed'em, Sasaki's fellow Headliner in the Beasts Pirates, also owns a mechanized sword, which he refers as Karakuri-to. Unlike Sasaki's, however, Holed'em's sword capabilities are unknown, although the anime gives it whip-like stretching abilities.