The Bat is defined by the .886 retracement of move XA as Potential Reversal Zone. The Bat pattern has the following qualities:
Move AB should be the .382 or .500 retracement of move XA.
Move BC can be either .382 or .886 retracement of move AB.
If the retracement of move BC is .382 of move AB, then CD should be 1.618 extension of move BC. Consequently, if move BC is .886 of move AB, then CD should be 2.618 extension of move BC.
CD should be .886 retracement of move XA.