TTR-SB released by Thunder Tiger in 2015 and discontinued in 2017 is based off the previous Thunder Tiger Neptune. This uses the same Water Tight container known as a WTC and brushed rolling pump, pump remote switch and sensor as the Neptune but with newer brushless main motor and larger brass propeller plus a 5000mah 4S LiFe battery instead of the Neptune's Lead acid battery given this Seawolf a runtime of around 50-60 minutes. This uses a FM crystal radio as 2.4ghz cannot penetrate water these have no longer been in production for many years the Seawolf uses the same FM radio from the early 2000s as the Neptune. Only small number of Seawolfs were produced with the limited components to make the FM radio as no manufacturer makes parts for FM radios anymore