Finis Z2 Gold Zoomers Swim Fins, Yellow/BlackThe Finis Z2 Gold Zoomers Swim Fins, Yellow/Black has been especially designed with a comfortable fit of 100% long lasting and durable natural rubber material, creating a soft and secure fit, inhibiting hyper-flexion. Made with its short blade, the Z2 Gold Zoomers encourages shorter and faster kicks while allowing just enough propulsion through the water. The Finis Z2 Gold Zoomers Swim Fins, Yellow/Black Forward Propulsion Hydro Channels efficiently propels you forward, while the specially designed fluid separator located on top of the fin, allows your foot to easily slice through the water reducing any fatigue on the down kick and quads. Whereas the Flex Box, which is located on the bottom of the fin, helps in catching water on your up kick, targeting and strengthening your hamstrings and gluteus giving you the desired muscle tone. Note: Female users should get one size smaller.