Gear ratios and Gear box length: 
19mm gear bpx length based on gear ratios:1/9.7 1/12.5 1/16.1 1/21.3
21mm gear box length based on gear ratios:1/26.9 1/35.5 1/46.9 
23mm gear box length based on gear ratios:1/59.2 1/78.1/103.1
25mm gear box length based on gear rations:1/130.1 1/171.8 1/226.8
27mm gear box length based on gear rations: 1/286.3 1/377.9 1/498.9 

Technical performance:
MBI-25A370-99-1284
Gear ratio: 1/99
Voltage range:3-12V
Working voltage:12V
No load speed:84r/min
No load current: 0.20A
On load:1.2kg.cm
On load current:0.80A
On load speed: 68r/min
Stall torque:6.0kg.cm Min
Stall current:2.0A

MBI-25A370-360-1226
Gear ratio: 1/360
Voltage range:3-12V
Working voltage:12V
No load speed:26r/min
No load current: 0.065A
On load:1.6kg.cm
On load current:0.403A
On load speed: 23 r/min
Stall torque:12kg.cm
Stall current:2.60A