RS2 Mercury works on door hinges, bikes, and trout. The RS2 Mercury mimics helpless emerging insects leaving their shucks. Used to the comfort of the sofa, lazy trout find it an easy meal to pick up and eat these stranded treats. Couple this with the Blue Winged Olive Parachute and Blue Winged Olive for a macho selection. When it comes to selective trout, it helps to cover the whole spectrum of the Baetis cycle.