I'm not sure if you will find one with a 1:1 ratio. You most likely will find that a gear set may be matched as in a 25/25 toothed set for 3rd or 4th gear (1:1). But since you have to turn the power 90 degrees inside the unit you will have another gear ratio to consider which will change the final output numbers.
Try this;
* Put a mark on the input pulley and a mark on the case so you can tell when you have turned the pulley one complete revolution.
* Mark the axle in the same manner.
* Turn the input pulley and count the number of turns the axle makes.
* Check each gear this way.
* Write them down. The one that is around 3:1 is probably the 25/25 gear set if it has one.