A 34H is a 34 band with an H cup — a deep cup that's hard to find on the high street. The band does most of the work (around 80% of your support), so if it rides up at the back or the straps dig in, it's the band to fix, not you.
We cut 34H for fuller busts, part of our full 34D–34K range. Not sure 34H is your size? Book a personalized fitting and we'll get it sorted.