Two things. It has the largest reception window in the range at 8.75 inches, so the laser finds it more easily on a moving arm, and it reads the dipper arm angle. It also gives a 9-channel display and four deadband settings rather than three.

ACE is Angle Compensation for Excavation. A standard receiver only reads true depth when the dipper arm is plumb - out of plumb, the laser strikes the receiver at a different height and the reading is wrong. The LR60 recognises the arm angle and calculates the actual bucket depth, so it reports the same correct depth whether the arm is plumb or not. That removes the step of stopping to plumb the stick before every check.

It mounts on the machine - on a mast, a blade or a dipper arm - and reads the plane from a rotating laser you have already set up. The receiver tells the operator whether the cutting edge is above grade, below grade or on grade, so nobody has to stand in the trench with a grade rod and the operator does not have to stop and check.

Deadband is the size of the on-grade zone. A wider band is quieter and steadier, which suits a first pass or rough grading; a narrower band is tighter and suits a finish pass. Measured from the centre on-grade position the settings are 5 mm (0.20 in) fine, 10 mm (0.40 in) standard and 20 mm (0.80 in) wide. Working from an offset on-grade position they are 12 mm (0.50 in), 25 mm (1.0 in) and 50 mm (2.0 in).

Offset moves the on-grade zone away from the centre of the receiver to wherever the laser is striking it. That means you do not have to physically move the receiver when the grade changes, and if most of your work sits above or below the reference you can shift the zone so the laser is in the window more of the time. On an excavator, setting on-grade high gives the operator earlier warning that the bucket is approaching depth.

The receiver will read a laser from 105 to 1200 RPM, but that is what it tolerates, not what works well. In practice you want 600 RPM as a minimum, and faster is better. The reason is strikes: the faster the laser spins, the more times the beam crosses the receiver every minute, and the more often the display updates. At a slow rotation the reading lags behind what the machine is actually doing. That matters most on a skid steer or a dozer, where the operator is making quick changes in elevation or travelling at speed - a slow laser leaves the display chasing the blade. On an excavator working one spot at a time it matters less. If your laser has a variable speed setting, turn it up.

Yes. These receivers are rated IP67 - sealed against dust and against temporary immersion in water - which is what keeps repair costs down on a machine that works in mud and gets washed.

Built-in clamps fasten the receiver to a square or oval mast and hold it even if the machine is slammed or shaken. Three mounts cover the rest: the CTO-MMM mini mount for backhoes, skid steers and mini excavators, the DM-20 bolt-on dozer mount, and the MM-1 magnetic mount for dozers and excavators. Call us and we will tell you which one suits your machine.

Yes, and it is one of the reasons contractors buy these rather than a full control system. The receiver comes off one machine and onto the next with the right mount. One receiver can cover a small fleet instead of sitting idle on one machine.

No. The RD20 pairs only with the wireless-capable W models - the LR30W, LR50W and LR60W. This is the non-wireless version, and the operator reads grade from the receiver itself. If you want the display in the cab, ask us about the W model before you order; it is the same receiver with the radio fitted.

Not from the front - they are identical. The W model carries a radio compliance label on the back and the case is marked. If you are unsure what you already own, call us with the part number and we will tell you.

Contractors-Tools.com, an authorized Spectra Precision dealer. We set these receivers up every week. Tell us the machine and the laser you are running and we will spec it before you order. Call 1-877-866-5721.