The KOBOLD flow meters and switches model DSV are focused around the rule of the well-known float kind flow meters with the exception of the ordinary decreasing measuring tube. This abolish the ordinary issues of managing the cylindrical float inside a tapering measuring glass. The novel outline counting the procurement of a properly dimensioned annular hole of steady width between the float and the flow tube has empowered the affectability to soil to be respectably decreased. This licensed instruments are given rather a tube shaped flow tube with conical slot around the periphery.