Sendt 1/4 inch (6.3mm) Male to Male Mono Effects Pedal Coupler, 3 Pack 3 pack all metal mono male to mono male couplers Great signal transmission. Space efficient all metal effects pedal couplers 1/4 inch (6.3 mm) male to 1/4 inch (6.3 mm) male couplers Great for use with effects/pedalboards!