They're not worth it is one statement. Another is that I haven't ever broke one prop since using them is another!!!!!!!![:'(] Never ruined another prop shaft since using them is another!!!!!!!!!!!1[:'(] I like to try lot's of stupid things real close to the ground. I'm never trying to land, it just happens sometimes when I'm doin stupid things. Anyone else agree with this and killed many prop shafts? Landing has little to do with it!!!!!!!!! And prop shafts get expensive and hard to come by when you do lots of fun, stupid things like I do............... YES, THEY DO WORK!!!!!!!!!!!!!!!!!!!!!!!