Works well in FF 55.0.2 droid 4.4.2
Needs long hold facility to hide buttons or Disable addon.

It works, but it scrolls really slowly and the are no custom options

This addon is exactly what I need, BUT it would be COMPLETE if you add an option to check/uncheck AUTOHIDE these 2 scroll buttons! It's uncomfortable to see them ALWAYS on every page! By the way, it doesn't work on all pages! Here, on Firefox addons website, the buttons DOESN'T show up at all! Thanks!