Window Replacement Part

I'm looking to properly identify my window replacement parts before I order. If you can give me the correct link, I'll order a couple now to confirm. If all is correct, I'll know which ones to order for the rest of my windows.

The metal of the part measures at 30 inches. It's also hard to see in the photo, but the stamp into the metal shows 29-3. I don't think it makes a difference, but the window it's lifting is 33"x33".

I look forward to your response.