The Nike Flyknit Trainer, a cutting-edge technology developed through extensive research into runner performance over the span of four decades, made its highly anticipated comeback in October 2017 under the name "Bright Citron". This reemergence marked the celebration of the silhouette's fifth anniversary, with sustainability taking center stage. In line with this environmentally conscious approach, the sneaker's upper is crafted from recycled PET bottles, while excessive materials are intentionally eliminated. The design further incorporates essential features such as a Flywire lacing system, contrasting Swooshes, and reinforced outsole pods.