Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: blade diameter
Document: Sharp, large diameter blade, works perfectly on every pizza I've tried it on. I expected this pizza cutter to work well and last almost forever. I treat my possessions with respect, but after just 6 months the plastic part that holds the blade cracked while cutting a pizza. I called Zyliss and they agreed to warranty it for me, but unless they reinforce the plastic handle, the new one will probably break quickly too.
Much sharper than the plastic blade unit I had.
After one use and careful storage the blade is so dull it will not cut pizza. Junk at its best.
Would give this 5 stars if there was a cover for the blade....big design flaw in my book. otherwise fine
It's amazing, it's a pizza cutter. Guess what, it cuts pizza! The blade disconnects and the entire blade can get washed!
It cuts perfectly.The cheese doesn't get inside of it because is tall enough.It is very easy to clean because the blade can be removed, but have to be careful because is very sharp.
Easy to use, great for cutting. Just make sure you put it where it is easy to reach. Blade is sharp and there is no protective cover.
Works well to slice pizza. The catch to open it is a little tricky, but I like how easy it is to clean once you remove the blade.
Have used it MANY times and it's still just as sharp as the day we got it. Also it's very convenient that the red handle opens so that you can thoroughly clean the blade.
Bought two - one for home, one for the vacation house -Simple to use, easy to clean - not so sharp you have to worry too much about the blade
Answer: 4"