These are very light, so weight is not an issue. (It never is with me. I'm a 194 lb commuter who almost always has at least an extra 20 lbs -- sometimes 30 -- in rack bags.) The lightness makes these a bit flimsy. They work OK, but you have to be careful, especially with commutertour tires that have very firm beads, and are tough to put ontake off the rim. It was very difficult to get these under the bead and get the bead over the rim while removing my tire.
This low-cost lever is my favorite. I've been using it since 1991 because it makes a single lever change possible, even with tight tires.
The lip for the tirerim side has the perfect geometry to get into the tire without forcing anything, reducing the worry of wrecking tirerim when changing a flat on the road.
True measured by me weight is 41 g 32 g levers 9 g case not 26 g as listed.
Case is very nice, levers don't break apart in bike bag.
Levers are solid not flimsy, don't flex significantly under stress.
I have used many different tire levers over the years. The park tool ones I have broken on a stubborn tire, but the koo stop levers have done the job over and over and over. I carry them with me all the time in my commute bag and trust them that if I get a flat, they'll get the job done.
It'll get your tires off, but durability is definitely an issue. If you have a stubborn tire, the cheap plastic will flex..I've tried Park Tool's levers and they're definitely more durable than the Kool Stop's.