To fit correctly measure the width of the window plus 30/40cm (12-16), this will ensure your curtains will comfortably cover your window. Fit your track or pole approximately 15cm (6) above your window recess and centre ensuring you have 15-20cm (6-8) either side of the window.
A keg is a fancy version of your basic barrel. In the factory, a sheet of stainless steel is rolled into a cylinder and welded together. Then, at the cylinder's midpoint, a set of ribs is pressed into it for added rigidity. Next, top and bottom steel plates are stamped out and likewise welded into place.
Lugs are made of copper, aluminum, or bronze. They are made for the smallest wire size, 26 gauge to the largest 2000 MCM. Lugs can be mechanical or set screw; compression or crimp, solder or weld; or clamp type. T&B, Burndy, Penn Union, Panduit, and 3M are some different manufacturers of lugs.