This tremolo control box can be used with many Hammond Organ models including A, B, C, D, E, BV, CV, B2, C2, RT2, B3, C3, RT3, A100, L100, and M100. It can be used with various Leslie Speaker models including: 122, 122R, 122RV, 222, 22H, 22R, 21H, and 31H (above serial number 5200). The control box is in fair original condition and is sold as-is and untested.