LeMahieu is swinging a Marucci AR13 Maple bat lately, which is a C271 cut, in a gorgeous natural flame-treated look. The 271 is the classic balanced cut, and its the same bat that Troy Tulowitzki swung back when LeMahieu was his double play partner.
With the medium barrel diameter of the 271, DJ is able to use DENSER (harder) wood than a bigger-barreled bat without adding weight, and this gives LeMahieu more control and a harder hitting surface. While the AR13 is unavailable, Baseball Express offers the RIZZ44 for $150, which I can say from experience is a tremendously well-balanced bat and similar to LeMahieu’s AR13.