Hotone Volume Expression 2 in 1 Guitar Effects Pedal Passive EXP Ampero Press Guitar Pedal SP-35Conventional external expression pedals often control only parameters of an effects unit, requiring the use of switches on the effects unit to change its status. Ampero II Press solves this problem with its built in single footswitch. And the optimized footswitch structure provides the excellent tactile feedback. About this item: Expression pedal with footswitch Independent footswitch and expression outputs jacks Passive design no power supply needed