What you need to know: these are specialist antennas for mobile applications - perfect for a Raspberry Pi based Stratux receiver, but a size vs performance compromise if you don't own a Cessna, Piper or similar light aircraft. However, two high-quality pigtails sweeten the deal, and both antennas work acceptably with strong local signals.
Background information and testing notes in the Manifesto, underlined text are links, bring you to a new page in a new window. Click / tap images for full-screen glory.
In the bag
Both antennas look exactly like small WiFi antennas found on routers and Internet access points - only visible differences are Nooelec sign and frequency designation, and SMA connector on the ADS-B antennas, versus no sign and Reverse Polarity SMA on the WiFi antenna:
Do not remove the outer plastic cover, as it might damage the antenna; it's surprisingly hard anyway, construction quality is much, much better than a cheap WiFi aerial's.
Receiving elements below - the large bottom one is a high-gain WiFi antenna:
SMA Male connector: works with equipment sharing that standard, such as rtl-sdr.com dongle, Nooelec SMArt, SDRPlay, handheld communications receivers etc.
Two pigtails: washer and nut on SMA end (finally...), angled connector for MCX dongles on the other end, 6" / 15cm 50 Ohm radio coax inbetween, heat-shrink tubing on both ends.
I won't fault you, dear reader, if you don't get ecstatic about pigtails. My mental approach to pigtails and adapters was "Get the cheapest" until I started using quality Nooelec pigtails, and the difference is heaven and earth - I connect and disconnect dongles a lot due to testing.
The same pigtail costs $8 at Noolec (link), so if you need these pigtails, you actually save money and get two antennas for free.
Larger version with 5 dBi gain, costs a bit more (link).
Doing so might violate local laws, and you'll crawl around a lot if you lose the small wire when unscrewing.
Discretion is the better part of valor - WiFi antennas, or rubber duckies were the weapon of choice for certain listening environments until I got these. Both antennas in this bundle work better than WiFi antennas, and smaller, easier to conceal and less expensive than a rubber ducky from a handheld transceiver.
The telescopic antenna found in the SMArt package (any telescopic for that matter), when extended a little bit was significantly better. 2,756 vs 1,517 total reports, 116 vs 66 total aircraft seen.
For general use, either the signal has to be very strong (e.g. commercial FM broadcasts) or you must be near the signal source. For example, local ATIS got understandable 1.3 miles from the airport, and conversations between Tower and landing aircraft only became clear very close to the runway.
Not recommended as a first antenna due to limitations imposed by small size. For a ready-made do-it-all, search for "SMA Male antenna" on your favourite online store and choose a telescopic similar to this $3 one (link).
Who's it for?
Create a WiFi hotspot on your tablet or smartphone, connect with a Raspberry Pi 3 and PiAware, add a battery bank, RTL-SDR dongle and this antenna for a go-and-take anywhere ADS-B monitoring station.
Is it worth it?
Yes, as an antenna pack for general use and ADS-B on the go.
No, it's not designed for maximum ADS-B signal reception performance.
Yes, for $14 you get two antennas and two SMA - MCX pigtails.
The answer is up to your wallet.