Thanks MNNB. I understand it.
It looks as if it were cooked.
Not really cooked, imho... My experience and testing tells me it's simply manufactured by using oversized 388D-1 mold instead of standard one. It doesn't feel oily, hard or dead like treated rubbers at all... I think it's simply a super-sized long pips manufactured for fun, the same as those giant table tennis paddles...
The enlarged pimples are a result of soaking the regular Dawai 388D-1 in chemical. On www.taobao.com
, these pips are sold as "二次加工大夥粒", meaning "treated 2 times large pimples". But each supplier treat the pips differently and their playing characteristics vary. Some are over-done and they become very fragile and will lose lots of pips during each playing session.
Typically, the enlarged pips are 2.5 to 2.6mm long and are very elastic and bends easily and quite fast. For a passive blocker, the 2.5mm version may not work for them.
There are some suppliers that provide the 2.1-2.2mm version, and these pips are slower and and provide better control. The problem is, it is very hand to find the 2.1mm version on www.tao.bao.com