Identify parts

Thanks for reaching out to us. It's hard to say without seeing a full view of the operator's arms but our 39-253LB and 39-438B come to mind. The video below will go over the differences between the two. The 39-451 cover and handle are compatible with these operators as well. 

If it's the hinge you need, I recommend you start by taking a look at the 36-048's specifications. Note, we recommend replacing the top and bottom hinges at the same time.