options of spectra s2 in market

Hi i am ordering spectra s2 through my insurance.
Do u ladies have any opinions on ehat should i be considering while ordering it
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1. I read it comes in a battery option also
2. Some flanges 
(Which size of flange will work for normal size nipples ,n i wear 36C nursing bra)
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3. Does it comes with double pumps?
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 Any other suggestions?