If your bike doesn't have an electronic cruise control, this is an essential alternative.
If anyone has ridden for more than an hour at a time on the highway, you know that hand cramps can and will happen. The throttle lock that comes stock on many bikes aren't all that practical.
The Go Cruise is an inexpensive alternative to a cruise control and a better choice over some of the other choices that lock your throttle. This one goes on your handlebar grip. That makes it easy to reach. Other reviews said it sometimes will slip or get loose. I never had any real issues with that on my last 2500+ mile trip. Sometimes I had to make micro adjustments, especially when riding up an incline or down a decline to maintain a constant speed. But on a straight road I didn't really have a problem.
I usually keep my hand resting on the handlebar anyway. So I'm always ready to react quickly if needed. What the Go Cruise does is give your hand the needed relief from having to keep your hand wrapped around the throttle while on long runs.
For $20, it's well worth the price and makes gobbling up miles on the slab much more enjoyable.