I don't know if this is the correct place to put this. I have never used a topit before and I would like to know what they are like. Do you need to be wearing a jacket? Do you toss the items in the topit? Are they detectable?

This has been discussed in depth a couple of times. Use the search function.

Short answer is that except for one version (Dan Sylvester’s jacketless Topit) that they are built into a jacket (OK I have built one into a Hawaiian shirt, but the shirt is worn jacket style, open over a t-shirt). If you vanished a bowling ball or six pack of beer into your Topit it will show. In fact many bulky objects will show unless you watch your body position.

In general, the Topit can be used to vanish and produce small items (Mike Ammar uses his for a wine bottle production and hides the bottle well).

Again, try the search function and read the discussions, the pros and cons about each type of Topit out there.