Irwin 2550 Series Magnetic Heavy Duty Box Beam Level Review

A premium box beam level with the innovative and practical Plumb Site feature.

Irwin 2550 Series Magnetic Heavy Duty Box Beam Level

Irwin 2550 Series Magnetic Heavy Duty Box Beam Level

Irwin has a well deserved reputation when it comes to levels. The company currently has 17 models in a variety of styles and lengths suited for just about any trade.
The most recent addition to their line of levels is the 2500/2550 series. The only difference between the two models is that the 2550 has six rare earth magnets imbedded on one side of the level so that you can attach it to any metallic surface for hands-free use. There is also a 2500E series level that has a digital angle display.
The 2500/2550 levels are available in seven lengths: 16", 24", 32", 48", 72", 96" and in a kit format that has both a 32" and 78" level. I tried out a 48" level, which is probably the most popular length for a general purpose level - it's practical for most framing and trim jobs and convenient to transport to and from, and carry around, a job site.

Left to Right: 1000 series, 2000 series, 2500/2550 series levels

While similar to the 2000 series, the 2500/2550 levels have a somewhat larger, more robust frame, reflected in their heavier, 3 lb-12 oz weight. The high-grade aluminum box beam frame design is what gives the 2500/2550 series its extreme rigidity and durability.
Check out the product video that shows a 2500 series withstanding the front axle weigh of a 3,300 pound truck, and supporting 730 pounds of concrete before bending. A bit over-the-top perhaps, but it does show the incredible structural strength of the level.

Precision machined edges          

The Irwin 2550 model 7371180, which I've been using for the last month or so, has an overall length of 48", and a 1-1/8" by 2-3/8" frame size. As you would expect on any professional level, both narrow edges have precision machined surfaces that are perfectly flat. They're smooth, but not so smooth that they'll slide about in your hands.

Six rare earth magnets provide superior holding power

On one edge of the level are six rare earth magnets that enable you to attach the level to any metal surface. These magnets provide very good holding power, so there really is no danger of the level falling, unless it's inadvertently knocked. The magnets are recessed just a hair's breath below the surface. And, it will take decades, at the very least, before there is any degradation in the holding power of the magnets.

Solid block acrylic center vial

There are three spirit vials on the 2550 - a center vial, a vertical vial on one end, and the innovative 'Plumb Site' dual view vial on the other end.
The middle vial is 17/32" x 1-7-16", and it's bright and easy to read. While acrylic vials can't be replaced, they are virtually unbreakable, and they won't leak. Irwin guarantees its vials to be accurate to within 0.029° for the life of the level. You'll also note that there is a continuous edge on either side of the center vial, which not only serves to protect the vial, but provides a continuous edge when you want to scribe a long continuous line with pencil or utility knife.

Side view of center vial      

The center vial can also be viewed from the side of the level, through a window that is roughly the same size as the port on the top edge. For some reason, the side view of the center vial doesn't look as bright as the top view - perhaps this is because the vial is surrounded by a field of blue (the top has an off-white plastic housing).

Vertical vial - also enclosed in a solid acrylic block   

The vertical vial is, like the center vial, encased in a second solid block of acrylic. It's slightly larger than the center vial, and equally bright and easy to read.

Bumper pads and a hole for hanging the level
Removable end caps
On both ends of the level you'll find rubber end caps, that provide some shock-absorption if you drop the level on an end. The caps can be easily removed for accurate leveling into corners - a very convenient feature. With the caps removed you can draw a continuous line 47-1/8" - just shy of the width of a sheet of drywall.
There are also rubber pads on each end of the level (though only on one side of the level) that keep the level from slipping when you lay it on a surface. And finally, there are through holes, lined with aluminum, that enable you to hang the level from a nail.

Large cushioned handles  

The two large (1" x 4-3/8") handles are cushioned - a nice feature - and replaceable should they become damaged. However, I did find them too narrow to use when wearing gloves.

Plumb Site dual view window      

The Plumb Site window is a fabulous feature, that once you use, you'll not want to do without. To be fair, this isn't a new feature - it's a trademark of Kapro Industries, and a number of companies have been licensed to use it.
The genius of the Plumb Site is that it enables you to view the plumb vial undistorted, through the narrow edge of the level, while standing flush in front of the level. You don't look directly at the vial, but at it's reflection in a mirror. This is a very clever idea, that makes it much easier to take more accurate readings. Of course, estimating how centered the bubble is in the vial is fairly subjective, but the Plumb Site makes it a lot easier than cranking your head to one side in an effort to take a reading.

Quicker, easier and more accurate readings with the Plumb Site

There really isn't much not to like about this level. It feels sturdy in the hands, has bright, easy to read vials, a continuous edge for scribing long lines, strong magnets for securing it to metal surfaces, and it has the innovative, and practical Plumb Site feature. Two features I wouldn't mind seeing on this level are a scale imprinted on the narrow edge and lighted vials. But, for around $70, the Irwin 2550 Heavy Duty Box Level is still a stellar performer.
Note: If you're looking for a lighted box beam level, check out the
Irwin 2000L, which has some of the same features as the 2550 (Plumb Site, continuous edge, .029° accuracy, removable end caps), but has a slightly lighter frame.


  • 1-1/8" x 2-3/8" x 48"
  • 3 lb-13 oz weight
  • High-grade aluminum body
  • .029° guaranteed accuracy
  • Plumb Site dual sided viewing
  • Continuous edge
  • Removable end caps
  • 6 Rare earth magnets
  • Limited lifetime warranty

COMPANY:Irwin Tools
SOURCE:Tool and equipment suppliers nationwide

Carl Duguay
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