I think you may be right, some translation errors.
explosive- bombs and fire works are explosive
expensive- cost a lot like diamond rings....and the women they are hooked to.
I will just add that the inexpensive (cost little) octos are pretty bad preforming regulators. They will supply you air but are not good to breath from for a long period of time. You really do not want one as your primary regulator and I personally do not one as my octo. In my opinion, a used set of regs that are the middle price range models from one of the major brands (Apeks, Aqualung, Oceanic, Sherwood, Cressi, Scubapro, Zeagle to list a few, there are more) is a much better investment than cheap (inexpensive) brands.