This is a quick and reliable solution for when you have got your ethernet cable's lock-tab broken but you do not want/have no means to re-crimp those plugs.
The idea came from this thing http://www.thingiverse.com/thing:972153 and I decided to make a "self-sufficient" solution. So here it is.
I have noticed, that when RJ45 lock-tabs are broken, the end, where the tab previously joined the plug remains. This design fixates that reminder as if the original tab.
I print it in translucent (it looks more suitable for such small thing) PLA from colorfabb.com .
My prints are at slow speed with 0.2mm layer height. I use the 7 layer raft and soluble attachment to the raft.
One notice - if you have your RJ45 socket hidden deeper into plastic enclosure (I have this situation in the case of my printer) then better use the file rj45_repair.stl . It is less flexing but there is no spring and it will get into the socket just fine (anyway you will not be replugging much)