Flowline is our latest addition, incorporating our best technical innovations in a comfortable, technical, yet affordable kit. The Flowline Long Sleeve Jersey is aimed at the enthusiast mountain biker with minimalist features, but the quality, fit and feel you expect from Troy Lee Designs.. Flowline is our latest addition to the MTB category, incorporating our best technical innovations in a comfortable, technical, yet affordable kit. The Flowline Long Sleeve Jersey is aimed at the enthusiast mountain biker with minimalist features, but the quality and fit you expect.