I have purchased many of these units over the years, and have never been let down. It has always exceeded my expectations for accuracy and performance. I first purchased this unit many years ago for an APRS tracker in a vehicle, and it worked for years stuck to the roof of a vehicle. It is fully waterproof. It has internal magnates, and says it's rated for something like 65MPH, but honestly, I don't think many vehicles could/would ever attain a speed that would peel this off a roof. It also has a spot for a bolt mount (also weatherproof) , if you want to get serious and bolt it down. It also does not appear to discolor paint, at least the paint on my vehicles. It has an internal rechargeable super capacitor or battery that retains date/time/almanac for some period of time being powered down, to help with acquisition upon power up. Because of this, it would always have very fast signal acquisition upon power up, always less than 1 minute, and sometimes just a matter of a few seconds, and worked everywhere, including many parking ramps (!!) and only failing to acquire signals in underground parking garages! After an extended power down of weeks or months, the internal power will run down, and expect it to take up to a few minutes to get a good fix. It survived summers, winters, car washes, etc, and never failed. I purchased several others for balloon mounted APRS trackers, and again, they worked well, where other GPS units would routinely have a hard time dealing with the massive signal refraction caused from the satellite signal bending effects of 120,000 cubic feet of hot air directly overhead from a hot air balloon envelope. Years later, several more were purchased due to the 1PPS out signal to create an array of several GPS timed NTP servers for some product development use, that proved to be so reliable, accurate and stabile, - greatly exceeding the reliability "enterprise" NTP GPS timed servers in our case, due to the fact that there are no separate antenna/cable/connector components that can be compromised by moisture/weather- that they were then retained past development for full commercial use in an enterprise setting. The waterproof hockey puck all in one design really can't be beat! Those units have been running 24X7X365 for many years, stuck to the roof of a metal building in the snow, rain, hail, sleet, ice, heat, sun, without any detectable known issues. All in all, if you need a WAAS enabled GPS unit for a project, this can't be beat. The only down side to these units is that you need to solder them to something (project board or connector) to use them, and you'll need a Windows PC with serial to run Garmin's configuration/firmware update utility if you want to change any of the unit's options (change baud rate, or change it to no 1PPS output if sat signal is lost, NEMA string output configuration, etc). The ones I've purchased always were advertised as connectionless, but they always came with a non weatherproof test connector/header that could easily be snipped off.