Here's a comparison photo of my size 26 toolbox vs 35 birkin. When the "wings" of the toolbox is out, its almost the same size as the 35 B, only tons lighter! I was really not sure of getting it as I found the shape a little awkard but DH and the very nice SA convinced me that I will love it. Now after using it, I think the toolbox is a really practical buy. Roomy but light and the shoulder straps gives additional options. The clasp is also easy to use so closing and opening it is not a hassle 
