RK3 - Dive FinsThe Apeks RK3 is a rugged thermoplastic rubber fin featuring an over sized foot pocket to accommodate drysuit boots and a spring strap for easy donning and doffing. The RK3 is available in four sizes: Small, Medium, Large and Super. We didn't give the RK3 fin a shoe size range as this can be very misleading. The environment that an RK3 is used in will tend to dictate the size of fin that you need, for example do you dive in a warm environment wearing