Look at your Arbiter Sports schedule and in particular look at the Level column. Part of what you see is an age/gender group like 11B or 14G which translates to Under 11 Boys or Under 14 Girls. However, in some cases, there is more information there in the form of initials or words. Those initials designate the league and are always a prefix to the age/gender group.
ISL – Idaho State League
RS – Rush Developmental League
Outback – ISL (Rec) formerly the Outback League
Outback-ISL – ISL (Rec) (increased fee)
BTT – BTT Youth League
BTT Comp – BTT Competitive U9 League
ST – Star Parks & Rec League
E – Eagle Youth League
ECNL – ECNL
BEAL – Elite Academy League
No initials – D3L and Tournaments
For example, if the level for the game you are assigned to is RS 14B, it means you have an under 14 boys game in the Rush Developmental League.
Hopefully, this clears up any lingering misunderstandings about which league your game is in. If not, let me know.