Trigger: Always bet the two most recent splits hits in one doublestreet.
these two hits should be during the last 10 spins.
so, it's a 4 numbers bet, two splits. if the third split is hit, bet is changed to those two last splits hit. and +1u progression
each trigger is played for 9 spins only.
progression +1u after 9 spins, -1u when hit (and the bet is kept for the next trigger)
the tendency is that is most cases the two most recent split hit in one ds will repeat.