I finally find a sunny day to test this insert. It is made by hard rubber, so compare to normal foam insert it is less likely to deform or break under high speed or heavy load situation. I test it in both my kyosho and ZH bikes. The steering response is very linear compare to the older "o-ring" or foam insert. In both corner entry and exit the bike feel more control according to steering input. And I am able to apply throttle earlier during corner exit. It is so stable I need to add steering travel. But by doing this I am able to lean more during corner. And it weight more than other inserts so I need to setup the ESC for more punch too.