Tymate RV Tire Pressure Monitoring System - M12-3 Tire Pressure Monitor System (0-87 PSI) with Solar Charge, 5 Alarm Modes, Auto Sleep Mode, LCD Display, RV TPMS with 4 Sensors, Easy to Install

After being told by my car dealer that there were no aftermarket TPMSs(Tire Pressure Monitor Systems) for my 2002 truck and spending $300 to have internal sensors installed in my 2015 car winter tire/rims, I discovered many aftermarket external TPMSs online. I could have returned my $300 internal sensors, but I decided not to because I like my car being able to monitor my summer and winter tires (on separate rims, so I only need to have the summer tires/rims swapped out with the winter tires/rims. Easy.Now, I wanted to have the external TPMS for my 2002 truck since internal sensors will not work with my truck. So I bought these. However, I wanted to have this TPMS also for my Prius as the factory internal sensors only send an alert when *only 1* of the 4 tires has *only low pressure* and no other information. It is a bit of an unnecessary pain to have to check all 4 tires for low pressure, if the low tire is not obvious, which often it is not.I decided to install this TPMS on my Prius, and I am very happy I did. Soon I will install this TPMS on my truck also.Installation was a bit of a pain, because I was playing around with all the buttons before installing the sensors and I goofed up the assignment of the sensor with the different positions they are labeled for: Front Left, Front Right, etc. I took me quite a while to reassign the sensors to their correct tires, which turned out to be very easy: just select a tire position and unscrew and rescrew the sensors. The monitor assigns that sensor to the correct position automatically.The video instructions online are spoken in Chinese (?) and the English subtitles are very minimal and nearly worthless. This needs to be addressed! Should have subtracted one star for this, but I am too happy overall with this TPMS.Both the monitor and the sensors are *much* smaller that I had expected them to be, and very happy about that. The hub caps on my Prius allow for very little room around the valve stems, but these sensors "just fit", fortunately. My box contained 4 dust caps for the sensors, but they are very thin and relatively flimsy, so I don't know if they will stand up very well to the changing seasons.As for tire pressure accuracy, I filled and checked my tires with an expensive Astro tire pressure gauge. I set them all at 38 PSI, and the TPMS monitor read all 4 perfectly at 38 PSI. Can't get much better than that! Of course the pressure changes while you drive, but that is normal. I changed the default setting from Bar and C to PSI and F. Very easy to do.It would really be nice if these sensors could be monitored while *not* driving, but I get it---that they need to conserve battery power and put them to sleep when the car is parked. You have to first drive "12.4 mph" for the sensors to activate and send their signals to the monitor. The monitor activates automatically when receiving signals from the sensors; so you don't have to turn it on every time you drive. The backlight also activates automatically in low light.I decided initially to not install the brass nuts used to supposedly secure the sensors tighter. Due the different in the brass nuts and my aluminum(?) valve stem, I am concerned about galvanic corrosion over time. On the other hand, it appears the the female connector on the sensor is also made of brass, so there might be corrosion anyway. Hmmmm, so I might install the brass nuts later, since leaving them off might not make any difference. The sensors do seem to be very snug when tightened down by themselves, with any air leaks.You cannot set the high and low pressure limits independently for all 4 tires. You set the *front* tires limits, then you can set the *rear* tires limits and then the spare tire limits. That works for me because the readings from the 4 tires are still *read independently*, telling you exactly which tire has dropped before whatever limits were set.According the another review this model is the latest, a monochrome display replacing the older, apparently faulty color display. OK. Actually, a color display could be distracting while sitting on my dash.I am hoping I will never need the USB cable to power the monitor. (The instructions say to charge the monitor with the USB cable before using the first time. OK; I did that.My manual says that it can "Monitor up to 7 tires." I don't know how that would be set up.I plan to install this TPMS on my 4-wheel truck soon. I also have a 2-wheel RV that I tow with the truck. When I do that, I will simply take 2 of the sensors off of my car and put them on the RV!Summary: I am quite happy with this TPMS, and if it holds up over the years it will be one of the best accessories I have ever bought for my car and truck/RV. To be able to monitor even just the air pressure and have an alarm go off if the pressure drops below the programmable limits I set is just great.

Overall, this is a pretty decent item. I've only had it for 6 months now, but I really like it. It's especially nice because it's pretty accurate and costs ~$50-60 (wait for a deal) and I don't have to waste money going to get new sensors replaced for $100+ a TPMS sensor. Overall, it was worth the purchase as it's very convenient to see the current pressure/temperature for each wheel (if you don't have that with your vehicle already).This product works by replacing your cap for the air valve with a sensor and nut. Once the cap is off, you thread on the [locking] nut and then put on the sensor hand tight. You then "loosen" the nut which winds up using friction to keep the sensor tight in place so someone (without the included 1/2" offset wrench) cannot remove the sensor(s). It takes an extra 10-20 seconds to add air into each tire because of this mechanism, but it's not a big deal.The unit itself comes with adhesive to secure to whatever surface you want which is very helpful so it doesn't move around easily. It constantly charges via the sun. Something to note: I believe the unit turns on when it senses vibration (via closing a door or starting the engine)--but can be turned on (e.g., the display) by clicking any of the buttons. It will then show whatever data was last recorded from your previous trip, BUT once the car moves it takes about 5 seconds of the wheels rolling to update the data (automatically) to the currents stats. Just be aware of that. It doesn't bother me, personally.The description says it has an accuracy of +/- 3 psi. That's an absolute range of 6 psi--a lot of room for error for my liking. Despite that error being apparently similar to other items on Amazon, I have found with my trusted digital tire gauge that this unit reads +/- 1 psi most of the time. That's really good.There's a lot of settings on the device that you can customize to your liking. Other reviews have stated that once it starts beeping (i.e., the tire pressure drops below a set threshold), the beeping will not stop until the pressure is increased. That is FALSE. All you have to do is hit one of the buttons on the top and it stops the beeping.***Due to the small space you have to tighten/loosen the "security/locking nut", you need the included 1/2" offset wrench (feels like just sheet metal or the type of wrench that comes with furniture). I have an assortment of tools and cannot find a tool that would suffice. Maybe a small open-end 1/2" wrench that is bent or an open-end crowfoot could do it. But a flare nut crowfoot or standard open-end wrench will not do it. I cannot find the included wrench anywhere; so if you lose it, it might not be fun. I WISH THEY WOULD INCLUDE 2 OF THESE WRENCHES IN THE PACKAGE.

We have a 2 axle, 38 foot travel trailer. We chose this unit for the repeater, and I don't like things on my dashboard, so low profile is good.It does work. It takes a couple of miles to kick in, but seems fairly accurate. Super easy install and setup. When there is an issue, it alarms, loudly, to get your attention.My only real issue with it might just be my own eyeballs. In the daytime/dusk hours when it's not backlit, it's hard to read, but the sunglasses and my greater focus to towing might contribute.The weird issues we've encountered... The first trip, it lost signal with a sensor, started alarming, and we pulled over do no reason (but, better safe than sorry). The more annoying one is that I kept the other two sensors in the camper as backups... I95 in south Carolina is quite bumpy, borderline violent in a heavy duty, and one of the "spares" started transmitting as 0 pressure and beeping loudly .....Great system as long as you don't keep the extra sensors in your camper while driving on I95 in South Carolina.