Technology

Wind Knot
The Wind Knot (風の結び目) is a rope with wind-creating properties that is tied three times. Untying one knot results in a light breeze. Untying a second knot brings a strong wind. Untying the last knot summons a squall. In the anime, Nami uses this rope in conjunction with her Perfect Clima-Tact to perform a technique that dispels an oncoming cyclone. Apparently the Wind Knot can be grown along with other knots in a special type of garden called a Weather Garden.

Self-Destruct Switches
A self-destruct switch (自己破壊スイッチ) is a mechanism that can cause an object to destroy itself or render itself inoperable after a predefined set of circumstances has occurred.

A switch was left in Vegapunk's old laboratory on Karakuri Island that went off when Franky caused the Nightmare of Baldimore with another one undisturbed in what remains. Another switch went off three years ago by Caesar Clown on Punk Hazard that destroyed the first two Research Institutes while the one in the Third Research Institute was left alone until Monet tried to set it off but was stopped when Caesar tried to kill Smoker.

Fluffy Balloon System
The Fluffy Balloon System (ふわふわ風船システム) is a device which allows Charlotte Flampe to float in the air like an actual balloon. The device was obtained when Big Mom was destroying other countries.