When you arrive at your hotel in Miami, ask the concierge or customer service desk, where the nearest reputable sports store is. The local mall is your best bet for finding a couple of different sports chain stores.
This is a listing of HRMs that are available from amazon. Look through the list and determine which model best suits your needs. Then write down which models you like and when you get to the sports store in Miami, you can ask for those models. And do write down 3-4 different models since you don't know what the store will carry. Most reputable sports stores will carry a small selection. So, you really must do your homework before you go. Check out the different models and decide which one you'd like before you get to the store. Be an informed consumer. www.amazon.com/s/ref=nb_sb_noss_1?url=sear