An L Bracket. The dimensions of the attached files are: 25mm x 25mm L with thickness 5mm and hole size of 5mm. But parameterizable if you have Autodesk Inventor.

Designed on Autodesk Inventor Professional 2013 (educational edition). Use parameter design table to parameterize and adjust dimensions in Inventor LBracket.ipt file. Printed with ABS on Makerbot Replicator 2X printer at 230C extruder temperature, 120C build platform temperature and layer height of 0.2mm (100% infill).