Sun Company Ascent Altimeter - Battery-Free Altimeter and Barometer | Weather-Trend Indicator with Rugged Aluminum Case and Reflective Lanyard | Reads Altitude from 0 to 15,000 Feet

This altimeter is great! One thing that is not super clear in the instructions is that you can calibrate the barometer using a screwdriver in the back of it. Check you local "altimeter setting" from you local airport ATIS or AWOS or the barometric pressure on any weather app. Note that this figure is adjusted for sea level, so you then need to adjust for you local elevation. I used a GPS altimeter and cross checked with a TOPO map. A rough rule is to subtract 1 inHg for each 1000 feet above sea level. -- You might not need to even do this. Just know that it is an option if the factory calibration ins't perfect. -- Once this is set once, you should not need to do it again, or very infrequently. You can then rotate the outer bezel to calibrate the altimeter to local known altitude before each outing or each time you hit a known elevation since this will vary as the barometric pressure changes. I came home today and reset my altimeter to the my known elevation and was able to see the current barometric pressure (look at zero elevation line matched to the inner orange ring for the standarized barometric pressure measurement, which is at sea level) The lines are close together, but I guessed the current barometric pressure to be 30.15 and when I checked my local airport ATIS it was 30.16. That is pretty accurate! I drove it up to the top of a 500-foot hill near me, and the altitude change was true to the actual landscape. Awesome and fun little tool. I look forward to taking it into the wilderness.

As far as the product, it is built well and accurate but to read it, you constantly need to know the exact altitude of your location to get the correct barometric pressure. You can't just set the barometric pressure and altitude at your current location and drive up the mountains and expect it to be accurate at the summit.

Check your elevation before you begin. Set the dial use it and stop complaining...

It doesn’t tell you what altitude you’re. You have to set it but to set you have to know what altitude you’re at and I got the altimeter because I don’t know what altitud e I am. So how do I find my altitude without an altimeter?

I bought one of these about 8 years ago and it's been working perfectly. The only problem is the numbers are too small. One of my favorite accessories.

I fined it hard to believe that it is 2023 and I can’t getAn accurate altimeter !What has this world come to ????

I bought one of these as a "Used, Like New" example. The altimeter moved slightly when changing elevations but was not accurate. I moved from 141 ft elevation to 470 ft elevation. The needle moved about 100 feet. The barometer never changed. I tried adjusting for altitude, but it still never moved. I gave it a couple of weeks, to see if it needed to acclimate. Home barometer was changing quite a bit as a low-pressure trough moved across our area. The barometer still never moved.I requested the return and Amazon did their part. I got the return code and mailed the unit back to Sun Company in Colorado. It took quite a while for the return to get processed and the refund sent to my account. I'll try another one, as I suspect that particular unit was faulty, and I'll update the review once I've had a chance to put the new one through its paces.

When we travel across country, it's fun to keep track of our altitude.