Looking for replacement of right and left

Thanks for posting. This casement window operator reminds me of the 39-253RB Encore Dual Arm Operator. You'll also need either 39-375 (folding) or the 39-451 cover and handle kit; this operator is not sold with a cover and handle. The opposite versions of each of these can be found tagged below this thread.

The piece at the end of the straight arm is the 39-529 Truth Hardware Track Slider, which is compatible with the 39-528 track.

Dimensions for 39-253RB