TM93 Trolling Valve
 
Mounts between the gearbox output flange and propeller shaft coupling. Controlled by a separate lever the multiple clutch plates within have pressurised oil forced between them opening or closing them allowing hydrostatic slippage and the ability to reduce the minimum shaft rotation of 500rpm down to a single rpm.
 
Especially of benefit when holding station or net fishing.
 
Optional on Beta 43, 50, 60, 70T, 75 & 85T.