Just tried the J3 40deg on my Yinhe V14 Pro. I played with the robot for a short while, but it feels quite good. It's nothing like Big Dipper though. It's a fast rubber. I'm used to H3 and Battle Max Pro 41deg, and this was faster and felt a bit harder, and semi tacky/tacky. Unboosted then. And it's harder than LAC.
I guess Attitude is trying to explain to mr. Zuhang what I tried some year ago
Now I use Big Dipper 38deg on my backhand, and I quite like 'em (boosted). It's a semi tacky rubber, and I find it strange that Attitude got some rubbers that almost didn't grip the ball. I played with BD for some years and always got quite good grip with these. I think they are too mushy for forehand in 38 & 39deg, and the 40 deg didn't give me the effect I wanted. Perhaps it's softer top sheet didn't go well with a harder sponge...