Level control of liquid substances, particularly suitable for use on tanks and/or purification plants as well as sewage channels, wastewater, discharges from septic tanks, industrial waters, and others, provided that they are free from sedimentation and compact stratifications that could prevent the float switch from the movement. Particularly suitable for those situations where there may be frequent excursions in the temperature between 4 and 60°C. The “SHUTTLE” float switch consists of a mono-block external body made of pressure-blown polyethylene, a 21(8) Ampere 250 Volts 50-60 Hertz switch positioned centrally on its own sealed chamber obtained from a polypropylene mono-block body sealed by over-moulding with injection of material of the same type. This chamber, being inserted in the “external-body” and subsequently sealed in the interspace with two-component closed cell expanded material capable of creating, in addition to high thermal insulation, a barrier against infiltration, allows us to consider that the float is made with a triple protection chamber. The “SHUTTLE” float switch, if requested, can be supplied suitable for use in the presence of oils, and in this case, it will be equipped with an adequate power cable.