The Can Fan RK series of fans use the same motors and air flow control as the RS range. They are encased in a moulded durable polymer body. It's a matter of personal preference for the type of casing you require, but the polymer casing has allowed for addition of the RK-S and RK-W fans.
RK-W (with Temperature Controller)
The integrated electronic thermo sensor on these fans helps to control temperature. The target temperature is easily set by the adjustment dial. When a variation of more than one degree occurs, it activates an increase or decrease in the speed of the fan until the target temperature is achieved again.
RK-S (with 4 Speed Controller)
The addition of the speed controller adds versatility. Each speed setting is factory set and calibrated to produce the most efficient output specific to each fan.