Collings SJ Custom Jet Black Top Tigerstripe Pickguard Old Growth Sitka/Bastogne Walnut w/Case #34996SJ Custom Blacktop Old Growth Spruce Small Jumbo Acoustic Guitar The SJ is Collings' version of what is commonly called a Small Jumbo. Although the 16 inch lower bout is slightly wider than a dreadnought, and the sides almost as deep, the tight curve at the waist creates in a very different sound chamber. SJs, especially examples in maple, typically have a more pronounced midrange response when compared to a dreadnought, making them ideal candidates