While most competition rules just specify a 2 piece bikini and some kind of parameter for the amount of glute they cover 2 Bros has some unwritten rules you will need to observe when selecting your bikini.
Here are the guidelines, lifted directly from their website for the bikini class:
"Competitors will compete in a two-piece suit. The bottom of the suit must be v-shaped. No thongs are permitted. Competitors can compete in an off the rack suit. All swimsuits must be in good taste. Athletes will be warned about improper suits and are advised to bring two (2) suits to check in. The fronts of the suits must be constructed high. Athletes will be scored down if the suit is not up to standard."
This should be all you need to know...but it is not...in my experience each show has a flavour and preference for many aspects of the bikini that just aren't in the rules. The 2Bros Pro shows are affiliated to the IFBB Pro league, and look to the NPC for aesthetics.
Check out my cheat sheet if you want to step on stage level pegging with your fellow competitors in a 2 Bros Pro show...
So here is what cut and style you should be wearing and how to wear it in a nutshell:
scoop front bottoms not too low
simple connectors worn high on the hip
Pro cut bum style (no thongs)
triangle cups are preferable but not obligatory
simple connectors on bikini straps
simple crystal designs, 1-2-3 colours max and no complex patterns
Colours are important too.
Generally if your hair is dark wear a bold dark colour. Greens, reds, blues and purples are strong on stage and are usually high in the scoring zone. Blondes stick to mid tone colours such as turquoise, reds, emeralds and royal blues. I would avoid gold, silver and pale colours like the plague unless they work REALLY well with your skin tone.
The bikini class in this division are very understated, in terms of crystal. Stick to a simple design such as an overall grid in one or two colours that stick closely to the chosen colour of your bikini. You could also have a mix of colours and AB colours, or perhaps an ombré design ( one colour transitioning into another) but make sure it sticks to the tone of your bikini.
Of course having the right bikini is only part of your overall stage presence, but it can't hurt...right?