Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: What is the battery life of the unit?
Document: Installs easily and synched with my watch with no issues. This is a good unit that works well. The issue is not with this, but the battery life on the watch. If you plan on doing LONG rides that last longer than your battery life, you are out of luck. Good concept, but will probably rely on a separate cycling computer.
Got it all set up in ~35 minutes.Once I got a new battery in the thing and gave up on the LED showing me that it was working before firing up my head unit again, it paired up automagically with the Edge 500 and has been working great ever since.Can't comment on battery life or overall long term durability as I've only logged ~500 miles with it so far, but it has seen significant water/mud spray so far with no adverse effects.
Works as expected. I have bought four Garmin GSC 10 Speed/Cadence Bike Sensors total, one for each bike. Easy to set up and maintain. No issues with devise or battery life.
My cadence monitor battery continually needs to be replaced. So much so, that I just gave up using it. I wish Garmin would come up with a better design that doesn't move around on your bike or drain the battery life so quickly.
For the price a very good and practical deal.I might add that I bought 2 of these one each for the road bikes I most often ride, for my fun rides I'll just keep using the old Cateye. In addition, given the 405's battery life while using the GPS, I'm hoping the sensor will help track my longer 100+ miles rides without the Garmin shutting down.
Battery life is fair at best, but the cr2032 watch batteries are cheap.I have owned 2 FR305 units, my first came apart on a bike ride and was ko'd by a car. They are pretty decent, and work well with running in clear skies. Although they also have issues, I did replace it when it was ko'd, the information I receive 95% of the time was worth purchasing another, plus I can move it from bike to bike to my arm when I run or hike.
I rate items based on three criteria - Does it work as advertised? Does the value justify the cost? Does it improve my life? I put my recommendation at the top, then answer those three questions below.RECOMMENDATIONI can easily recommend this set of gadgets for any cyclist with a Garmin GPS unit.
I replaced the battery and it worked perfectly, but it is sad to have to replace the battery on a brand new unit, but I guess that's why most products come without batteries.Overall, great product and I am very glad I bought it.
My GSC10 arrived w/ a dead battery and either the install instructions refer to a non-existent LED that blinks when either magnet passes the sensor for a short period of time after resetting the unit or my sensor shipped w/ a dead LED.
Again, it arrived from Amazon with a dead battery. So, plan on spending about $4 extra to get a working unit. Also will mention that some new bikes won't fit this accessory as well. The distance between pedals and the frame are much larger on the new bike so I have to tilt the unit way over.
Answer: I don't know yet, it still has the original battery from when I bought it.  Two years ago I think.