The 30E bra has a bigger band than the 28E bra. The 30E bra has deeper cups than the 28E bra, but they are about the same width.
Comparing a 30DD Panache Tango Pure Underwire Balcony (3761) with a 28E Cleo Bella Balconnet Bra (7001)
Bras I Hate & Love: What Does Panache Have to Offer? (Brand Overview)
30F - Cleo » Mimi Padded Balconnet Bra (8091)
Cleo by Panache Women's Blossom Balconette Underwire Bra, 10581, Raspberry, 32E at Women's Clothing store
Bras I Hate & Love: What Does Panache Have to Offer? (Brand Overview)
Spotlight on Panache and Cleo
Spotlight on Panache and Cleo
Asher Underwire Balconnet Bra
Cleo Asher Balcony Bra - Latte
Bras I Hate & Love: What Does Panache Have to Offer? (Brand Overview)
Description Uses the UK sizing system. This brand starts with a D cup in most styles, then continues D, DD, E, F, etc. up to a UK K cup. Some styles
Panache Tango Balconnet Bra in Black
30DD - Freya » Deco Moulded Half Cup Bra (4232)
Bras I Hate & Love: What Does Panache Have to Offer? (Brand Overview)
Comparing a Panache Tango Ii Balconnet Bra (3251) with Panache Tango Balconnet Bra (9071) in 34FF
Review] Cleo Asher 28F vs Marcie : r/ABraThatFits