Power button for the Samsung Galaxy S2. You have to print both parts and put the 'pilar pulsador' inside the main part. It can take some skill, but it is possible to put it in, believe me. The just slide in the button and close the mobile's lid. It works nearly as good as the original.
Printed in PLA with 0.3 initial layer (that's the only layer for the main button area). 0.4 mm nozzle but you could probably get a better print with 0.3 or 0.25, even better if your printer supports 0.2.