Step Audio brand 5-pin MIDI to TRS cable. 
 
Straight MIDI connector.
Right-angle 1/4" TRS connector with tip active only (ring is not connected).
 
Cable length is 1.5 feet not including connectors.
 
Red is a MIDI to TRS, tip-active cable that works with all Meris pedals as well as the Strymon Riverside, Strymon Sunset, Strymon Iridium, Strymon Volante, Empress Echosystem, Empress Phaser, Empress Reverb, Empress Tremolo2, and Bondi Art Van Delay, and likely many others.
 
Note: Meris and smaller Strymon pedals require you to configure the EXP jack as a MIDI Input. See the Pilot Wave Setup videos for those pedals for instructions.