Look at the cam module it should say RSH3,RSH4 etc. Match the number with the chart below. Then max the poundage on the bow and take it to a shop and have it measured on a weight scale. Nice thing about the Element,Code,Instinct, and Truth I is that you can micro adjust draw length. ie RSH3 will adjust from 29-30 and so on.

Element-
RSH1=31in
RSH2=30in
RSH3=29in
RSH4=28in
RSH5=27in
RSH6=26in
RSH7=25in
RSH8=24in