This impressive new fin gets its name from the smoky transparent panels on its long split blades. They are a bit more flexible than previous versions of the Atomic Splitfin, but still generated the highest thrust measurement of all the fins in this review. The Smoke on the Water fins also tied for the fastest speed score among open-heel fins and slashed through the slalom course with a top-three performance. In ergonomic tests, it was one of only two open-heel fins to earn an Excellent rating from test divers for Acceleration, and it also earned the highest score possible for ease of donning and doffing, thanks to the new spring straps with oversized finger grip. Firm rubber rails produce great power with little effort and provide stability with all kick styles.