Park Tool's INF-2 Shop Inflator is a highly recognizable tool found in many bicycle shops. While it is full-featured and has the distinctive blue Park Tool color, it is, however, fairly expensive at $134.95. That's quite a bit for the home mechanic. A few other air compressor inflators sell for less than half of that.
Each of these alternative inflators uses the same 1/4" I/M connector to fit standard air compressors and pneumatic line fittings, and a trigger that dispenses air and controls the rate of inflation, just like the Park Tool INF-2. Some offer the same functionality as the Park INF-2, while others achieve a much lower price, but also have reduced functionality. Let's take a look at 3 options:
Prestacycle Prestaflator Professional - $59.95
The Prestacycle Prestaflator Professional model is the closest direct competitor to Park Tool's INF-2 on the market. Like the INF-2, it has a built-in pressure gauge and handles both presta and schrader valves. The INF-2 has the advantage of changing between presta and schrader by simply flipping the tool over, while you change out a threaded tip on the Prestaflator Pro to switch between valve types.
The Prestaflator Professional does have a significant advantage over the INF-2, interchangeable tips. For example, you can change out the presta tip to an (included) blower tip, useful for using your air compressor for cleaning up dust in your shop, or inflating pool toys. This is a nice value-add that's impossible with Park's INF-2.
This same tool also comes in a Digital version at $79.95, which offers identical functionality to the Professional model, but adds a backlit, digital pressure gauge that's very easy to read - a nice upgrade for working in dark garages or basements.
Prestacycle Prestaflator Mini - $36.95
The stripped-down Mini Prestaflator from Prestacycle is one of the least-expensive inflator heads on the market. It reaches this price point by getting rid of the built-in pressure gauge as well as the dual presta/schrader compatibility. Instead, it comes in dedicated presta-only or schrader-only versions that can't be converted.
Most importantly, you still get the trigger-pull feature to control the rate of air flow. This model is appealing if you use your air compressor setup for seating tubeless tire beads and not daily inflation, thus making a gauge un-necessary. Similarly, if you use a floor pump with a gauge to set the precise tire pressure, you may not need a gauge on the inflator head at all. If so, the Prestacycle Prestaflator Mini is a good way to save some cash while still keeping the most important functionality.
Arundel Shop Inflator - $64.95
Arundel's Shop Inflator for Presta valves does one thing, and does that one thing very well. It uses a trigger-style design to control the release of air from the compressor, and features a built-in pressure gauge. It's sort of a hybrid between the Prestaflator Mini and Professional models, another competitor, and comes in at less than half the cost of a Park INF-2.
There is also a version of the Arundel Shop Inflator for Schrader valves. Each version of the Arundel Shop Inflator is a dedicated tool that handles a single valve type, and they are not convertible between styles.
Arundel's Shop Inflator is a great compromise if you want a PSI gauge on your inflator, and your fleet of bikes all have the same valve type.
Each of these 3 alternatives to Park's INF-2 is a worthy addition to your home workshop.