In this photo, Mike Kerr is playing a Gretsch G2220 Electromatic Junior Jet II bass, which he confirms in [this interview](http://www.notreble.com/buzz/2014/08/21/out-of-the-black-an-interview-with-royal-bloods-mike-kerr/). He also uses an all black version for live performances as well [as seen here](http://nocountryfornewnashville.com/wp-content/uploads/2014/03/393A8674.jpg).more
The Gretsch Electromatic G2220 Jr Jet II is a shortscale (30") bass that has dual TV Jones style humbucking pickups. A pickup selector switch, along with tone and volume controls make for a nice clean setup. Not a lot of knobs, just delicious growly lows. The best thing about this bass is how easy it is to play. The balance and feel are spot on, and the shorter scale makes it extremely fast. One of the best values, great for a beginner, but obviously perfectly at home with a pro as well.