Very well made, not too tricky to install, look nice, and help protect the bike in a tip-over (used twice). To engage them, you let go of the throttle, turn the knob about half way, and twist the throttle back to the desired spot. The Throttlemeister should hold the throttle in position now, while allowing you to twist it in either direction with little resistance. You can tighten the knob if the throttle starts to slip (and the bike to lose RPM). To disengage the Throttlmeister, you twist it to the "off" position and the throttle is freed, snapping back to the idle position.
Installation took me about 1.5 hours, most of the time being spent cutting the end off the rubber grips. This is best done with an old-style rasor blade, or similar cutting tool. You make the cut perpendicular to the axis of the grip on the very outer edge, along the fine molding line. This will expose the inside of the handlebar and you can then proceed with the installation. When doing this with the heated grips, you should be particularly careful not to stray inboard of the molding line.
Getting the lock to engage properly (right side only) is a little tricky. The instructions caution you to keep a gap between the Throttlemeister's bushing and the throttle sleeve equivalent to the thickness of a credit card. According to the company, this is to account for expansion of the plastic sleeve when it gets hot. I discounted this advice initially since I did not believe plastic would expand that much to justify the gap. I was wrong. Expansion does occur. When you install, make sure the throttle is locked about halfway through the tightening process.
Do I use the throttle lock? No. I guess I have a light touch on the throttle and my wrist/hand never tire, even on a 500+ mile day. I probably will use it when I do an IronButt run. For an alternate solution, you should go to Two Brothers to see their electronic cruise control.
Simple to install, but very time-intensive. You need to remove both side panels, the top panel, the gas tank, and more. One caution. The installation diagram enclosed with the kit, as well as the tank removal instructions in the OEM shop manual reverse the gasoline hose pinching sequence. Do what BMW says and there will be gas all over the place. Put the clamps on the opposite hose and you'll stay dry. The grips work beautifully, period. home