The Mouse is pretty much right on here. The SLAR2 is the cam used for the 30" draw lengths for both the SQ2 and the Q2 but it can also be used for the 31" draw lenth Q2XL.

To get a 29" draw length for the SQ2 you will need to get the SLBR2 since there is no adjustment for their cams you will have to get a new one.