Size is the difference
http://i.ebayimg.com/images/g/k4oAAOxy4fVTDGKe/s-l500.jpg
Condition : brand new
Size : SKG-38 : 130 x 40 x 27 mm (5.1 x 1.6 x 1.1 inch) SKG-27 : 150 x 50 x 27 mm (5.9 x...