Cutter knife Decompression toy (auto knife) Portable This is a replica of RiveryMFG Zero. (Search YouTube for the above to see how it works) This is a very rare and easy-to-use cutter knife that "manually extends" and "retracts with one touch" after work. Thank you for viewing. This is a resale of a personal purchase from overseas. I think the price is higher than overseas products. Please consider only if you are okay with that. I do not have deep knowledge about knives. Also, I cannot answer detailed questions. Knives and other blades, except for the purpose of camping or fishing, seem to be prohibited by law from being carried. We also refuse to sell to those under 18 years old. We will accept price negotiations for this product, so please request it from "Price reduction request". However, returns and claims are not accepted.