Yamaha DTXpress/DTXplorer/DTXtreme

Inputs 1 to 8 can use dual sensor pads, the original kit came with single
triggers, so hence the 'mono' connection leads.
Inputs 9 & 10 need a stereo splitter lead to make them totally separate, but
you could still plug in a dual triggered pad.

NB:The latest  version of the kit has a dual sensor snare pad, and cymbal
pad.

You can still use your pads with other manufactures, providing there is a
gain function to match the output of the Yamaha pads with say, for example,
a Roland type unit, and of course the reverse is true.