But enough of the history lesson – let’s get to work! The shop is full of cars than need repair, so let’s see what the Proto can do.

First Impressions

Needless to say, it’s not possible to get a new tool and let it sit in the box for even a few minutes. Before getting down to more serious work, I held the 90 PSI max Proto up to the IR and found it to be even slightly smaller. Remarkable. At just 2.9 pounds and an overall length of 4-13/32-inches, it really seems to push the size limits. However, it is just a skosh heavier than the IR at 2.4 pounds.

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You’ll notice a red rubber ring around the front of the housing, rubberized material around the back, and a fully rubberized handle that combine to protect all points of the wrench when laid on the concrete floor. It features a variable speed trigger just in front of the forward/reverse switch, which can be switched just as easily by the left hand as the right hand, and an integrated three-position regulator. Exhaust is released through a grate at the bottom of the handle.

The specs are also impressive. The Proto 1/2-Inch Drive Pistol Grip Mini Impact Wrench produces 635 foot-pounds of breakaway torque, a blow rate forward of 1,500 BPM, a free speed of 10,000 RPMs, and average air consumption of 4.5 CFM.

Catching Some Air

I hooked the Proto to a hose and tightened a few lug nuts to get a sense of what to expect. I couldn’t believe my ears – was it ever quiet! After a long career in shops full of high-pitched buzzing, whizzing, and whooshing sounds from pneumatic tools – and the inconvenience of throwing on some ear protection only to have to take it off to listen to an engine or communicate – the Proto’s noise output was like a (very quiet) choir of angels. I even think I saw a glowing light behind it! There’s another review floating around out there that highly praises this tool except for the noise output, saying it’s loud. I can’t agree.

But I don’t want to get ahead of myself. After all, the quietest tool of all could be one that doesn’t work. It was time to see if the Proto 1/2-Inch Drive Pistol Grip Mini Impact Wrench was up to the tasks of the shop.

Speed and Power

When tightening, The Proto was as fast as any impact wrench I use. We’ll talk about the ergonomics of the controls in a moment, but suffice it to say for now that the three-position regulator only governs the tightening, or forward, function of the wrench. Loosening, or reverse, is full power. Its variable speed trigger gives you the utmost control, instilling confidence that the gun can handle the lighter duty tasks, too. This is an important point: I could have a beast of an air wrench that could crank down with incredible force, but if I had little control of the power, I could easily bottom out threads or generally damage parts. Especially since the Proto’s size will allow it to reach more places around a vehicle than a traditional air wrench, it’s nice to know that it can have both power and finesse where appropriate.

One of the jobs I had was a wheel bearing that had a pretty tight axle shaft, and the Proto pulled it right off. In fact, during the course of the review, I didn’t have any task that the Proto couldn’t handle.

Controls

Aside the from the size, the stand-out feature of the Proto mini impact wrench pistol grip 1/2″ drive is the integrated forward reverse and regulator controls that can be easily reached with one hand – and ambidextrously at that. It takes just a few minutes to get used to it, and it’s quite user-friendly. Proto’s designed this wrench such that it doesn’t favor right handers or left handers.  Adjustments can be made without even moving the hand from the handle. You just flick the direction or turn the dial for power. It’s really pretty slick.

Pro Tip

Be sure to follow the manufacturer’s guidelines for injecting grease into the Proto to ensure a long tool life.

Feel

Half a pound is not much weight difference – and the balanced feel of the Proto makes it feel as light as the IR. You might be able to tell the difference holding the wrenches simultaneously, but in practice it’s a negligible difference. The overmold grip is textured and comfortable. And gone are the days when a misplaced exhaust system would blow back brake dust and dirt into your face – the bursts of air coming from the bottom of the handle direct all that stuff away from you.

In addition to all of these great features, there’s also a small hanging hook in the box that is really the icing on the cake. Snap the hook around the Proto’s housing and let it hang instead of setting it down.

I didn’t think I’d like an air wrench more than my IR, but I found myself reaching for the Proto. Proto has improved upon the air wrench in just about every way with this tool.

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The Bottom Line

The Proto Mini Impact Wrench is a 90 PSI max which seems to strain believably at just 2.9 pounds and an overall length of 4-13/32-inches.  It produces 635 foot-pounds of breakaway torque, a blow rate forward of 1,500 BPM, a free speed of 10,000 RPMs, and average air consumption of 4.5 CFM. A rubber ring around the front of the housing, rubberized material around the back, and a fully rubberized, textured handle protect it from wear. The Proto features a variable speed trigger, behind which is and one-handed, ambidextrous forward/reverse switch and a similarly designed three-position regulator. Exhaust is released through a grate at the bottom of the handle.

It’s really hard to find a weakness in this air wrench. It was well-balanced and did every task I asked of it with ease. The power packed into this little tool is remarkable. Once you understand the controls, you can work more efficiently.  With either hand the user can adjust them on the fly, hence single-handed operation. Moreover, you can work in more places around the automobile because of the wrench’s compact profile.

What can I say – the Proto has replaced the air wrench I thought was my new favorite just a few months ago. Although slightly smaller, it is half a pound heavier, but it’s hard to notice. At $318 you might wince slightly, but a few turns with the Proto will make you forget all about it.

Proto Mini Impact Wrench 1/2-Inch Drive Features

• Rubber bumpers for durability
• Variable speed trigger for optimal speed regulation
• Easy-to-use one-hand forward/reverse switch with integrated three position regulator
• Comfortable rubber injected overlay grip is resistant to oils and acids

Proto Mini Impact Wrench Pistol Grip Specifications

• Model number: Proto J150WP-M
• Drive size: 1/2-inch
• Breakaway torque: 635 Ft-Lbs
• Blow rate forward: 1500 BPM
• Free speed: 10,000 RPMs
• Average air consumption: 4.5 CFM
• Weight: 2.9 Lbs
• Overall length: 4-13/32 Inches
• Price: $318.94