Very simple bracket to fix the "filament monitor" ( http://tunell.us/ ) on the back of the Ultimaker 2 using the two holes already present to fix the Z-axis microswitch.For all the info about how to use on UM2, you can read starting from here:  https://ultimaker.com/en/community/view/7436-more-information-during-print?page=10&sort=#reply-120082