RIO MAINSTREAM TROUT SERIES SINKING FLY LINERIO Mainstream Full Sink Type 3 Fly Lines The RIO Mainstream Full Sink Type 3 is designed for anglers who need to consistently fish deeper in lakes and reservoirs or maintain depth during fast retrieves. With a sink rate of 3 to 4 inches per second, this full sinking line helps keep your fly in the strike zone longer for improved success with subsurface presentations. Tailored for beginner and intermediate anglers, this line features a slightly