This is actually an old Boss/Roland frame as I used to have this same designed pedal as a stereo volume pedal. And line6 has closed up said appropriate holes.
The original intention was to use it with the Firehawk FX for wah with the on board pedal to control my volume. Though I hadn't checked to see if they could be assigned differently, In all applications the EX 1 became volume & the onboard pedal became wah which is not the result I was looking for. As a volume pedal the EX 1 is extremely notchy, no smooth travel/taper, period. With more guitar players buying software/apps that require expression pedals, there are a few sturdier crafted pedals that appear to be more forethought & less afterthought which the EX 1 is obviously afterthought.
But I gave it 2.5 because though not great, it does work, & I know a keyboard player who seems to be in need of an expression pedal most times when he shows up for rehearsal. So, here's an okay loaner. :-/