The RK3 HD fin is the latest in the RK3 range. It is made
from a higher density (HD) material than the standard RK3
which makes the fin stiffer and negatively buoyant, ideal for
drysuit diving.
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 wetsuit boots, or are you
walking across pebbled beaches and wearing a drysuit and rigid dry
boots? Both forms of footwear may be a UK size 9, but will take up
different amounts of space in the fin foot pocket.