Yeh, try to practice with this!
All you'll get is wiggle wiggle...
IT FLIPS EVERYWHERE!!!
  

If anyone want to make them a little more stiff, buy thick metal wire/rods, cut a starter hole in them and then force them into the sai to act as a skeleton. They will still be low impact and have a rubber cover.  

These are just what they are implied to be RUBBER PRACTICE SAI! They are useful for working out the movements, but I have to agree with other reviewers. These could have been just a bit less pliable. They bend just a little too much, so I'm looking for a way to beef them up a bit, without adding too much weight and still keeping them safe to use. Sai movements require wrist snaps in lots of cases, and these things are way floppy when used in that manner. Still they serve a purpose. I don't have to grab real sai every time I want to practice. Also for what you get they should probably cost a bit less. 18 dollars is a bit too much to ask for these in my opinion because they are so floppy/pliable. The manufacturer needs to think about a different approach to making these as well if they plan to keep selling these.  

I am a traditional Shorinjuryu practitioner. I hate the idea of using fake sais but living in my dorm i could not keep real ones. I bought these for kata and kata only. But they are not good enough even for that. Other reviews say they just arn't good enough for contact, but the truth is that the are not good for anything. They are extremely floppy and using them to slowly study my movements i found that they don't even keep form. They just flop around. Plus they have a terrible rubber smell that did not go away for months until i threw them out. If you MUST use fake sais, buy plastic ones.  

This may be good for somebody who just wants to practice by themselves. However it is SO rubbery that it has no use in sparring, it will not be able to black an attack of another weapon.   

These are pathetic. You would be better off buying Sais made of paper than these. If you just want some to practice indoors with, there ok, but my dojo is into contact and they broke so easily.  

These Sai are the exact size and shape of other Sai. They are very safe. I used them to instruct my nine year old daughter and she put together an excellent kata for her age using them alone.
They are almost TOO flexible, however. After a half hour of handling during practice they become droopy from the warmth of your hand and flop around. We noticed cracks in the rubber within the first week and reinforced them with electrical tape. In all fairness, she won a second place at a tournament with them right before they cracked enough to come apart.