This is a heavy duty impact wrench set which really gets the job done on heavy and medium duty projects. The 1/2” impact gun made light work of busting loose the crankshaft damper bolt on a Buick V6 I was working on. I have been gradually building up a collection of Milwaukee M18 tools and these two are a great addition to my workshop.\nThere is a little difference in weight between impact guns with the ½” weighing in at 7 1/2lbs while the medium duty 3/8” comes in at around 5 lbs with the 5 amp/hour battery loaded in. In practice, the ½” is going to be very useful for heavy duty work on engines and automotive such as differential pinion nuts, ranch/farm equipment etc. while the 3/8” medium duty is more practical for longer use as it doesn’t weigh as much. \nI found that I went to the ½” for heavy duty fasteners like crankshaft damper bolts and motorcycle fork stanchion bolts where the maximum of 2,400 impacts per minute got the fastener loose without spinning the crankshaft or fork damper tube. For the rest of the tear down on the motor, I relied on the 3/8” as it was more compact and the lighter weight wasn’t as tiring to use.\nThere are 4 impact settings on each gun. For the ½” gun, setting 1 delivers up to 700 rpm and 1,300 impacts per minute which will tighten or loosen a fastener up to 650 ft-lbs. In mode 2, the ½” delivers up to 1,300 rpm and 2,200 impacts per minute which will tighten or loosen a fastener up to 900 ft-lbs. In mode 3, the ½” gun delivers up to 2,000 rpm and 2,400 impacts per minute which will tighten up to 1,100 ft-lbs or loosen a fastener up to 1,500 ft-lbs (1,600 ft lbs if you are using a Milwaukee Forge battery). Mode 4 is more of a ‘failsafe’ mode for making sure you don’t overtighten a fastener as it backs the torque way down to break off at 50 ft-lbs while still delivering 1,500 ft-lbs of loosening power.\nFor the 3/8” gun, setting 1 delivers up to 1,250 rpm and 900 impacts per minute which will tighten or loosen a fastener up to 200 ft-lbs. In mode 2, the 3/8” delivers up to 1,950 rpm and 2,100 impacts per minute which will tighten or loosen a fastener up to 300 ft-lbs. In mode 3, the 3/8” gun delivers up to 2,575 rpm and 3,100 impacts per minute which will tighten up to 550 ft-lbs or loosen a fastener up to 600 ft-lbs. Like the ½” version, Mode 4 backs the tightening torque way down to 35 ft-lbs. Mode 4 is good if you’re working with hex head or Torx head impact sockets as it should avoid deforming them.\nI found that the button that controls the impact setting was a little on the small side, so I ended up removing my work glove to change the settings as it wasn’t very easy with it on.\nI noticed that when I broke the nut loose on the crankshaft damper, the gun was delivering high rpm and impacts per minute and then slowed once the bolt broke loose to avoid the situation where the nut shoots off the threads in a fraction of a second and disappears into the workshop somewhere. I also found that the LED lights around the drive adapter were helpful. Finally, while it doesn’t have a bearing on the performance of the tools, I really thought that the embroidered Milwaukee logo on the carry bag was a high quality touch.\nThe tools are made in Vietnam and are covered by Milwaukee’s 5 year limited lifetime non-transferrable warranty which covers wear and tear or failure of the tool arising under normal usage and proper maintenance. To qualify for warranty, you need proof of purchase and will also have to ship or bring the tool to an authorized Milwaukee service center. The battery cells are made in Malaysia, Korea and Singapore and further processed in China and come with a 3 year limited warranty.