I currently don't breed feeders on a large scale, so these are only available if you are also ordering mantises.
The "mixed size" option comes with dubias in a mix of both the size you ordered and some smaller ones (if not already the smallest size), giving some allowance for roaches molting after arriving while you feed off the appropriately sized ones to your mantises.
Dubia Roaches
Be aware that dubia roaches are illegal in Florida, so they will not be shipped to Florida.
If you are only keeping some feeders rather than starting a breeding colony, you do not need to set up any particular enclosure or provide extra heating. You can keep the roaches in any ventilated, smooth-sided container, and feed them fruits/veggies. Any that will also provide hydration work well.
Warmer temps may cause them to grow faster, while cooler temps may help slow them down if you need to keep them at a current size. (Do not put them in the fridge!)