Troy Lee Designs Flowline SE Helmet – Stealth Black X-Large/2X-LargeTroy Lee Designs Flowline SE Helmet Stealth Black X Large 2X Large. MIPS equipped and eMTB rated Flowline SE sets the standard for safety within a modern minimalist design achieving a five star safety rating from Virginia Tech. With 14 vents an anti microbial liner and a Fidlock magnetic buckle system Flowline SE is the workhorse of trail helmets. Mips B Series protection with dual density EPS and NTA 8776 E Bike certification 3 Way adjustable