ACDelco ToolsACDelco 3/8” & 1/2" Heavy Duty Digital Torque Adapters with Buzzer and LED Flash Notification – ISO 6789 Standards with Certificate of Calibration (1/2” (14.8 to 147.6 ft-lbs.))

GREAT product design. I really like this tool. Comes with a nice blow molded, custom fitted, plastic case. The case has with what appears to be a substantial clamp. You can display torque readings in newton-meters(N-m), foot-pounds or inch-pounds. It uses one CR2032 coin battery and will auto shut-off after 60 seconds of no use.I own 4 different mechanical torque wrenches (3x Precision Instruments and 1x Sears Craftsman). I estimate I have spent over $500 for these wrenches - including the occasional calibration. The cost to calibrate one of these wrenches can run from about $60 on up to almost $100. So, paying for just one calibration of a mechanical torque wrench costs more then buying one ARM602-4. Therefore, I believe his tool represents a great value. The published accuracy for the ARM602-4 is 2% in the CW direction. My best Precision Instruments torque wrench is 3%. The big disadvantage with the ARM602-4 is its size - it will not fit in similar tight places that a mechanical ratchet torque wrench can fit.When I received my ARM602-4, I checked my other torque wrenches. I have a relatively new ( a couple of years old) Precision Instruments 1/2 inch split beam that agrees well my ARM602-4. But when I checked my old Sears Craftsman 3/8 inch, I found it was WAY off (but it has been almost 10 years since I had it calibrated). Yes, it is not evident which tool will have the most accurate torque measurement - but I think it safe to assume that a brand new ARM602-4 will have been recently tested for calibration.I work as an engineer on new product development (but I spend my spare time wrenching). I believe the product design team hit it out-of-the-park on this design. Durability? I can not say yet - I have only had it about one month. But of course, I would not kick it around on the garage floor. But I do not kick my mechanical torque wrenches around either. With the twist grip style torque wrenches - if you drop them when the spring is not tight - you could knock them out of whack. And then you would be looking at a new calibration. Torque wrenches - including this tool - should be handled with much more care than any standard ratchet or wrench.I have had nothing but problems with the click mechanism sticking on my Precision Instruments 3/8 inch wrench. EVEN after Precision Instrument "repaired" this wrench in 2014. So I appreciate the fact that the ARM602-4 does not have any mechanism that clicks and releases.One thing I have learned, since I purchased this tool - is to SLOW down when attempting an accurate torque setting. This ARM602-4 can quickly capture a peak torque value. So if you quickly snap tighten your click style mechanical wrench you will see more of a difference in readings. I believe the difference can be explained by your technique and the fact that humans have a much slower response than electronics. By the time you feel the click and stop tightening your mechanical torque wrench - you can easily overshoot. So, I have learned to slow down - and I can now achieve much better agreement between a recently calibrated mechanical torque wrench and this electronic torque tool.This has been a great purchase for me. I has me re-thinking the value of mechanical torque wrenches. If you do most of your torque settings where you have adequate clearance (like engine builds with the engine mounted to a stand or wheel lugs) the ARM602-4 maybe a better choice then buying one of the old, unreliable mechanical click style torque wrenches.

This review is written from Lagos, Nigeria for the ARM602-4 with 1/2" drive.I ordered this product when it was time to replace the cracked cylinder head gasket on my '09 Toyota Corolla with the 2ZR-FE engine. The product arrived in excellent condition and included the two batteries needed to operate it. The seller had earlier sent me instructions by e-mail on how to use it. It also includes an owner's manual with clear instructions.My impressions: it is easy to use. It is easy to learn how to use. It doesn't take you more than a few minutes to begin implementing what's written in the owner's manual (You, of course, do read manuals). Once you install the batteries you are ready to pop your square drive in and torque all sorts of things. There is a digital readout that's clear and easy to read in daylight; there is no backlight for dark places. The buzz that informs you about your target torque is loud and clear for probably most situations you'll find yourself. When you approach 90% of your set torque setting the beep begins and remains until you reach your preset torque in which case the urgent beep becomes a long buzz.You'll want to play with this tool when you first use it to get a feel for how far above torque you get it. There's a 'Peak' mode as well as 'Trace' mode - Peak mode saves a reading of the highest torque you've applied; I liked clearing this each time to see a new peak reading at the next attempt. With a few attempts I learnt how to slow down rotation to bring me as close to matching preset torque as possible, give or take. The Trace mode allows you see the torque reading in real time if that's what you want. You'll have to adjust the device to account for rotation so you can still see the screen while turning a bolt.Now, here is the catch: from my photo you can gauge the size of this tool - it will be impossible to use it in a few (or many situations) depending on the space in your engine. It was easy to employ for cylinder head bolts, camshaft bearing cap bolts, my right-hand engine mounts, intake manifold and then some bolts on the timing chain cover. The problem is that it was too large to allow me torque some bolts on the timing cover, exhaust manifold and alternator. I used it on most but the aforementioned few I had to torque by "feel". Also, this tool is calibrated for 20N.m - 200N.m (14.8 - 147.5 lb-ft). I found that all those 10mm bolts that required much smaller torques I just tightened by feel - the device won't register a readout until you reach 20 N.m, even when in trace mode.Another reviewer suggested to use this as a calibration tool for your other torque wrench instead and save yourself any headache. I do agree that another torque wrench may be needed to complement this.Over all, I am satisfied. This was all I used for the head gasket job for my car and I am pleased.

This seems to be a quality unit, and also seems quite accurate and easy to use. There are a couple of modes: TRACE (displays torque in real time), and PEAK (displays the highest torque after use). There is also an alarm feature, so you can dial in a desired torque, and you will get visual (lights) and audible (alarm) when the value is reached. You must be very careful to go slow and not torque beyond the set value (it won't stop you like a conventional clicker wrench).IMPORTANT: The operational AND alarm range is ~15 ft lbs to 147 ft lbs (20 Nm to 200 Nm). The packaging (and specs on the ad) report an operational range starting at 4 ft lbs (5 Nm), and an alarm range starting at 15 ft lbs. But that's an error. The older units worked this way, and would display lower toque values in Trace mode. But recently manufactured units will NOT display any value under about 15 ft. lbs. I talked to the manufacturer to confirm this is by design, and packaging has just not been updated. By the way, these are made by Durofix (in CA), and licensed by ACDelco. So if you need to measure lower torque values, get the 602-3 model (which will start at ~ 6 ft lbs). And if you are troubled that you cannot see these lower torque values, keep in mind it's probably not reliable even on the old units where you can. No torque wrench should be used in the bottom 10% of it's range... or at least, you should be aware that it will not be as reliable or accurate in this range.I purchased this to calibrate my own torque wrench more so than to use as an actual torque wrench, and it seems to work quite well in this capacity. I'm taking away one star just because of the confusion with the operational range.. they really should ensure that the unit is advertised and marked with the appropriate range.