screen latch

I have an old, enclosed porch with vertical sliding windows. On the bottom window there is a latch/catch on both sides. You push down on both latches simultaneously with both thumbs to release the latches from holes inside each sidetrack to allow windows to raise or lower. These latches attach to the window frame with a screw that allows the latches to pivot. I'm trying to find replacement latches, can you help?? Or point me in a direction to find these.