You need to be more specific but try this!!! Here is a link.

http://www.ktekcorp.com/dnn20/Default.aspx?alias=www.ktekcorp.com/dnn20/ktek

http://www.ktekcorp.com/dnn20/Default.aspx?tabid=54&productTypeId=8

Vibrating Fork Level Switches

Vibrating Fork Level Switches Utilize a Piezoelectric-Driven Tuning Fork that Exhibits a Large Change in Resonant Frequency when Immersed into a Liquid or Bulk Solid Process. A "Smart" Microprocesso-Based Electronic Unit Keeps the Sensor in a Resonant State as it Changes from Dry to Wet or Wet to Dry. An Important Feature of this Switch is that its Resonant Frequency is not Significantly Affected by Coating on the Fork Until the Space Between the Forks is Bridged. Applications Include Redundant High/Low Process Levels without Concern for Parameters, such as Specific Gravity, Dielectric Constant or Mounting Position of the Sensor. GP50 Vibrating Level Switch for Powders and Granular Solids Model GP50 The GranuPoint 50 is a Vibrating Level Switch that Detects the Absence or Presence of Dry Bulk Solids in Bins, Silos or Hoppers. The GranuPoint 50 is a Compact and Robust Design, Suitable for Top or Side Mounting. The Constant Vibration of the Fork Tine Provides Self-Cleaning Characteristics for Products that Do Not Coat or Cake. The Unique Design of the Fork and Crystal Asembly Eliminates False Level Readings. The Model GranuPoint 50 can be Used in Products that do not have Heavy Build-up on Forks. The GranuPoint 50 can Handle Dense Materials, such as Cement (80 pcf) to Extremely Light Products like Styrene (2 pcf). A Wide Range of Applications are Also Found in Dry Food Processing. More...

Below is the specifications for Endress &Hauser's model no.

Liquiphant S FTL70 in a/c to IEC 61508/IEC 61511-1

The Liquiphant S is a Vibration level limit switch which can be used in all liquids

	for process temperatures from -60 °C to 280 °C (300 °C for max. 50 h cumulative; without temperature shock limitation)
	for pressure up to 100 bar
	for viscosity up to 10000 mm2/s
	for density of 0.5 g/cm3 or 0.7 g/cm3, other settings on request
	foam detection on request

The function is not affected by flow, turbulence, bubbles, foam, vibration, solids content or build-up. The Liquiphant is thus the ideal substitute for float switches.

FTL70:Compact design, also for pipework

High corrosion-resistant AlloyC4 (2.4610) is available for the fork and process connections for applications in very aggressive liquids.

EEx ia, EEx de and EEx d protection enable it to be used

in hazardous areas.

Many more are there , try to search in Rosemount and ABB .

Look at Vega too (usual disclaimer).