I know I may have to duck after asking this question. I tandem feed and therefore make TONS of milk and will be returning to work at the end of the month. Are there any bottles other than Medela that fit the PISA pump that might hold more milk than 5.5-6 oz? I can already fill a 5 oz bottle on one side some of the time. Once I'm at work, I'm afraid I'll overflow them if I'm not paying attention.