Description
The Kell-Strom KS5549 PRO 360 Digital Protractor is a high-precision electronic angle measuring instrument capable of providing instant digital readings for level, plumb, and any angle across a full 360° measurement range.
Built with a precision-machined aluminum housing, the PRO 360 provides a rigid and lightweight platform that protects the internal digital sensor while maintaining the accuracy required for aviation maintenance, machining, fabrication, and precision mechanical work.
Inside the unit, a liquid-based electronic sensor and onboard microprocessor continuously analyze changes in orientation as the tool moves. The processor converts these measurements into clear digital angle readings displayed on the LCD screen.
The tool operates in a standard reference mode where level is displayed as 0.0°, but users can quickly establish a custom reference angle using the ALT ZERO function. A HOLD feature also allows the current measurement to be locked on the display for easier recording or inspection.
To simplify readings, the full 360° range is divided into four 90° display quadrants, allowing the instrument to maintain exceptional precision throughout the measurement range.
Unlike many electronic measuring tools, the PRO 360 can be verified and recalibrated directly in the field using the Superset procedure outlined in the included instructions—no factory service or special fixtures required.
The KS5549 comes complete with a protective rigid carrying case for storage and transport.
Key Features
• Full 360° Measurement Range
Reads angles across the entire 360° range, displayed within four 90° quadrants.
• High Accuracy Digital Measurement
Delivers ±0.1° accuracy at level and plumb with a maximum error of ±0.2° across the range.
• Precision Machined Aluminum Frame
Durable, lightweight housing designed for professional environments.
• Automatic Display Orientation
LCD display flips for easy viewing when the tool is used upside down.
• ALT ZERO Function
Quickly establish a custom reference angle.
• HOLD Function
Freeze the current angle reading for recording or verification.
• Field Recalibration Capability
Users can verify and recalibrate accuracy on-site without special equipment.
• Protective Carrying Case Included
Functions
• ALT ZERO (Alternate Reference)
• HOLD Function
• LCD Digital Display
• Directional Arrows for Level and Vertical Indication
Specifications
Part Number: KS5549
National Stock Number (NSN): 4920-01-420-6291
Accuracy
±0.1° at Level ±10° and Plumb ±10°
Maximum Error: ±0.2°
Resolution
0.1°
Battery Life
Approximately 500 hours using one 9V battery
Repeatability
±0.1°
Cross Axis Error
Minimal
Operating Temperature
-5°C to 50°C (23°F to 122°F)
Storage Temperature
-20°C to 65°C (-4°F to 149°F)
Weight
10.2 oz (289 g)
Typical Applications
• Aircraft maintenance and alignment checks
• Engine installation and rigging measurements
• Precision machining setups
• Fabrication and structural alignment
• Mechanical inspection and verification
In The Box
• Kell-Strom KS5549 PRO 360 Digital Protractor
• Protective Carrying Case
• Instruction Manual
• 9V Battery
