what kind of accessories should i use on or in my box?
On or in? You can use polyfil inside the box to fool the sub into thinking it's bigger. If that's what you mean.
Has anyone's child swallowed a foregin object?
I ate tons of crap as a kid. Batteries, nuts, screws you name it. You took her to the hospital for a coin? THats a bit overprotective.
I need to change some car accessories of my car .I need some thing good for the same .?
We don't know what type of accessories you are looking for. JC Whitney has a bunch in their catalog. good luck.