Engineered Sensors Tedeco Products by Eaton Aerospace Engineered Sensors Business Unit

Engineered Sensors
Tedeco Products

Tedeco Sight Gages: Prismalites® 

Tedeco Division prismatic sight gages provide rugged, reliable, low cost monitoring of machine fluids from a convenient location, usually at the top of an engine oil tank or gear case. Typical usage is to obtain a rapid and accurate FULL or LOW indication depending on whether fluid is PRESENT or NOT PRESENT at the prismatic cone. PRISMALITES® are normally installed for top viewing of oil, hydraulic fluid, or coolant level. However, they are equally effective as bottom viewing sight gages. Appropriate designs are also usable as side viewing liquid level indicators.

Low or Empty Indication  

Fluid monitoring, low or empty liquid level indicationWhen there is no liquid over the prismatic cone, incident light entering the viewing port is reflected over the prism. The bright image is readily interpreted as EMPTY or LOW liquid level indication. For those PRISMALITES® that have a red insert in the tip, the indication 
will change from black to bright red as 
the liquid level drops from FULL to LOW.

Full Indication

Fluid monitoring, ful liquid level indicationWhen the prismatic cone of a PRISMALITE® is covered by a liquid, there is no reflection within the prism, hence the viewing port appears black. The dark image is readily interpreted as a FULL liquid level indication.

Colored Insert and Short Prismalites

Colored Insert Prismalites®

Colored insert prismatic sight gagesIn this family of Tedeco PRISMALITE® gauges, a color insert causes the viewing port to change from black to red as the liquid level drops below the prismatic cone, thus providing a stronger CAUTION or WARNING liquid level indication.
® in this group contain a long, clear acrylic prism in a brass body. They are suitable for temperatures to 185°F (85°C) and pressure to 30 P.S.I. All models are suitable for top or bottom viewing.

Sight gage allows monitoring liquid level closely

Model Thread A


M1335F* 1 - 11½ NPT 1 3/8 1.00 2.75
M1229AG 5.50
M1335EG 6.75

*Furnished with plastic protective cover for external lens.

Short Prismalites®

Sight gage is side mounted in gear case or crank caseShort PRISMALITES® are most often mounted in the side of a gear case or crank case when the oil level must be kept high to provide adequate splash lubrication and cooling.
® gauges incorporate a glass window and a short acrylic prism in an aluminum, steel or brass body. Because of their short lengths, they are rarely installed as bottom viewing gauges, but can be used as side viewing liquid level indicators. Short Prismalites are resistant to “oil staining”  in addition to providing very distinct HIGH or LOW level indicators.

Ideal for side viewing of lubrication systems

Model Thread A


Body C
M1524A ¼-18 NPT 5/8 .34 Aluminum .57
M49JB 3/8-18 NPT ¾ .57 Aluminum .83
M36K ½-14 NPT 7/8 .57 Steel .95
M1253 1-11½ NPT 1 3/8 1.00 Brass 1.26

All dimensions are in inches unless other wise specified

Back to Sight Gages

liquid level sensors, indicators, breather vents, pressure sensors, gages, diagnostics

Home | Liquid Level Sensors | Snap Action Fill Caps | Breather Vents
Sight Gages | Magnetic Debris Detectors | Lube System Diagnostics
About Us | Contact Us |

Engineered Sensors — Tedeco Products 
24 East Glenolden Avenue - Glenolden, PA 19036
E-mail: • Orders: 800-837-0475
General Information: 610-522-4000 • Fax: 610-522-4063

©Copyright 2003 Engineered Sensors - Tedeco Products

Website by Advance Design