Well, there are 44 models and 29 of them have two knobs. Since you seem to have one that matches with the BOSS colour code and it seems like it isn't the CR 2, it must be one of these:
EX 2 Exciter
FL 2 Flanger
FL 3 Flanger
MC 2 Micro Chorus
MC 3 Micro Chorus
PS 2 Phase Shifter