The compound shown is 2,3-dibromobutane (no configuration specified). The total number of isomers of molecular formula $\mathrm{C}{}_4\mathrm{H}{}_8\mathrm{Br}{}_2$, counting all constitutional isomers and all stereoisomers (enantiomers and meso forms counted separately), is

Butane skeleton: 1,1-, 1,2-, 1,3-, 1,4-, 2,2- and 2,3-dibromobutane (6). Isobutane skeleton: 1,1-dibromo-2-methylpropane, 1,2-dibromo-2-methylpropane and 1,3-dibromo-2-methylpropane (3). That is 9 constitutional isomers. Stereoisomers: 1,2-dibromobutane has one stereocentre (2 forms), 1,3-dibromobutane has one stereocentre (2 forms), and 2,3-dibromobutane has two equivalent stereocentres giving meso plus a pair of enantiomers (3 forms). The other six have no stereocentre. Total = 6 (achiral constitutions) + 2 + 2 + 3 = 13.