This is the perfect swim cap.
 
The reason I chose arena and their Moulded Silicone Swimming Cap to make this cap is because no other brand makes swimming caps that are this high quality. Most importantly it is comfortable, no matter your head shape or how much hair you have, this will fit perfectly and stay comfortable no matter how long your training session or where you are swimming. It also is moulded which makes it wrinkle a little bit less than the usual standard silicone swim caps out there. This means you can race in this cap if you want to (a lot of women wear this on the international stage if they aren't a fan of the race caps because of having longer hair) and of course, wear it to your heart's content in training. I may be bias but I also love how this cap looks!