Third EyeBicycle Chainwatcher with Universal Clamp,Black

This works as intended but is a pain to install.The screw head refuses to line up with the hole on the plastic which is an indication that the metal band is sitting too low. I found that I had to tighten the metal band a fair bit, then push up the band and screw head up on the plastic ring.Another tip, the hole is too small for a typical flat head household screw driver. You need a flat head that is 4mm or smaller.As others have also mentioned, a philips head would have been better than the flat head.

Why do I state that this item a necessary safety requirement?And please note, I use my particular Terra Trike experience......but this item applies to all bike / trike configurations.Why?.. I'm a long time bicycle rider, before going to a Terra Trike, and years ago, in college, on an all Campagnolo equipped Schwinn Paramont, on a sunny clear day, in Denver, Colorado, in traffic, I came within inches of being run over from behind when I dropped my chain, in traffic, dropped chain jammed, and it was a hill so I slowed fast and came to an unexpected STOP and the front seat passenger in the car immediately behind me, grabbed the steering wheel and steered the car away from over running me, because the driver was looking to the left.So this is important, Especially in urban biking / triking environments.........so read on.........One of the "problems" of a large number of gear combinations, as in 27, on a bicycle and especially a tricycle configuration, is that you end up being at the extreme of front dérailleur movement plus extreme of rear dérailleur movement plus not real tensioned chain and sheer length of chain.In combination, all together make it easy to drop your chain off of your front and smallest chainring.Especially on a trike with a triple chainring front and a much longer, than a bicycle, chain and with two pairs of idler wheels to get your chain "way back there." In that configuration, a slight mis adjustment can cause you to easily drop your chain off of your innermost and smallest front chain wheel, when you shift hard and fast.And then you either abrupty STOP and or you can't move forward without stopping to untangle / unjam your chain and then to get the chain back on any front chainring, so you can move forward.Especially, if you had to drop down to your smallest front chain ring, FAST, because a traffic light changed, on an urban street. Or, you had to change your gearing abruptly to a higher gear (smaller front chainring) as you really had no room to get up to a better hill climbing speed because three little kids wandered in front of you on a very busy bike path.Note, I was a kid once so I don't complain about them, not learning or realizing that you don't drop in front of other riders on a crowded summer Sunday on DC Metro's Mt. Vernon Bike Path.This little item prevents you from dropping your chain and it may save you from injury.And in my case NEVER, dropped a chain, since I installed it, in over 5,000 miles of urban riding.It's not a substitute for keeping your front dérailleur adjusted, as it will wear and cause drag, if you let your dérailleur / shift cable get out of line.But until you can check and adjust your gear, it gives you a better "margin of error / cheap insurance," and you might need that in a situation, like urban street riding in auto traffic, where you absolutely can't be futzing with your bike or trike because you just dropped your chain off of your smallest and innermost chain ring.Because you could come to an abrupt HALT with an automobile or other biker moving toward you from behind. Yes I know the ratchet inside your rear cogwheel / cassette will let you glide forward...but what if you are on a hill, or you have to really move because it's now a green light ahead?And that is really not a good place to be.So for this item's relatively cheap price, it may, at minimum, save you from embarrassment of a fellow cyclist making a nasty comment...or a nasty auto driver leaning on an auto horn....or, if nobody behind you is paying attention, from getting hurt, and possibly hurt really badly due to being "rear ended" by a biker or automobile because your chain dropped and you came to an abrupt STOP.Thus I consider this a safety item now.

This item will work only on a limited type of bikes. The small chainring must be above the lower V of the frame by 2" in order for it to catch the chain. Sorry, not for use in most carbon fiber bikes (the catch is way above the chainring).Look at the picture in the box and compare with your bike.

Works great. As others have said, it's a pain to put on. That's because the poorly designed location of the tightening screw is such that the bike frame interferes with the ability to line up a screw driver to tighten the screw. My solution was to quickly grind an extra Allen wrench into an improvised low profile 90 degree screw driver as shown in the pics. You can also buy a 90 degree screw driver. Then, it's easy to tighten.

This item is a great inexpensive way to reduce chain drops off of the chain rings. You'll never know it's there or how much it's working. It's just like insurance. But you'll probably notice over time that you don't have chain drops.Item can be some what of a challenge to install.Recommend installing the clamp first with the screwhead on the chainring side facing forward but only getting it started with a couple of turns. Then install the plastic chain guard over the clamp. Tighten the clamp until it is one or two turns from being immovable. Then rotate into place for final turns of the screw to secure it in place.

I bought two. It took a bit of care to put on a small bike because the spot to tighten the clamp is underneath the derailleur and between the tube and the chainrings. A right angle screwdriver might help. It works a treat. The chain hasn't fallen off even with an awkward double or triple downshift that would have dropped it in the past.

It works. Simple idea, but last few times I dropped my chain, it scratched up my frame, and bent my chain to where I barely got back home. I have dropped my chain a few times with this device and I was able to get it back on while still pedaling and without any further damage to my bike.

These are very good for preserving your sanity on long rides.