Loop Resistance Tester comparison series – part 1.

Part 1 in our Loop Resistance Tester comparison series looks at the difference in the size & weight of the only two tools approved by The Boeing Company – the legacy ‘yellow box’ LRT and the new kid on the block, MK Test’s ExLRT.

Size matters!

Lightening the load

A Boeing-approved loop tester that’s 14kgs lighter than the LRT?  That’s a weight off your shoulders!

The yellow box LRT loop tester in your facility has been anecdotally blamed for back, neck and shoulder problems due to its weight.  The ageing design means its size isn’t suited to MRO field use, yet up until now it’s been the only Boeing-approved tool for loop and joint resistance testing.

Introducing the ExLRT

Introducing the ExLRT – it weighs just over 3kg (6lbs).  The legacy LRT weighs over 17kg, a difference which is the equivalent to 74 iPhones (or 140 croissants if you’re an Android user).  Believe us when we say you will really appreciate what a huge difference this is.

The difference in weight between the ExLRT an the legacy LRT is equivalent to 74 iPhones; 140 croissants; 32 NFL footballs or 39 cans of coke.

Musculoskeletal conditions are the leading contributor to disability worldwide*.  In 2018/2019 alone, 498,000 UK workers suffered from work-related musculoskeletal disorders**. 

Bearing these statistics in mind, MRO operators frequently tell us that the LRT weighs them down – it’s a large tool to be moving around a hangar, and it isn’t fit for purpose with modern health and safety principles in place. 

The photo below shows how the weight of the 2 different loop testing tools affects the posture – the difference is clear.

Size matters

It’s not just the incredible difference in weight which makes the ExLRT easier to handle than the LRT.  Take a look at this photo showing the two tools (that’s our BLRT tool in the centre).

Line up of LRT, BLRT and ExLRT loop testers
Line up of LRT, BLRT and ExLRT loop testers

The overall dimensions make a big difference to how operators can move, handle and operate the tools.  The ExLRT can be placed much more closely to the plane for example, and it can easily be lifted for placing on a suitable surface.

LRT355 x 355 x 55mm
14 x 14 x 22 inches
0.07m3 17kg
ExLRT150 x 200 x 300mm
6 x 8 x 11.8 inches

Beside the size and weight of the ExRT, there are so many other features which makes it a next-generation loop resistance tool perfect for MROs. It’s packed full of elements designed to make carrying out loop testing easier and quicker:

Full of features

To lighten the load even further, we offer wearable solutions for the ExLRT.  A harness and belt clip provide flexible, ergonomic options to suit the many positions and angles operators find themselves in.

The ExLRT is classified as Intrinsically Safe, so can safely be operated in Class 1 Div 1 (Zone 0) environments.  Its outdoor use rating is IP54 so it’s dust and water splash protected.

The screen is large and backlit so it can be read no matter how dim or bright the working environment is.  Talking of dim lighting, the probes have LEDs for even easier operation. Push button controls on the main unit and the probes make the ExLRT very quick to use – operators can accept a reading and move onto the next test in seconds.

Fed up having to plan for a 2 month calibration turnaround from BAE?  ExLRT’s calibration kit enables a typical onsite calibration time of just 30 minutes.  A return-to-base calibration with MK Test is usually just 72 hours.


In short, the ExLRT is a light, modern loop resistance tester designed for end-users.  It’s Intrinsically Safe and is approved by The Boeing Company. 

That’s a weight off your shoulders, right?

To learn more about the ExLRT, visit our dedicated product page here.

*World Health Organization