The "gadget" you are talking about to use in mojitos is called a muddler.
Here are a few links for you to look at (I LOVE mojitos - wish we could get together and have one!!!!..........or 5
muddlers (all 8")
wooden or plastic muddler, you choose
- it doesn't say how long it is though
Basically, they are all the same. And they are cheap too!!! LOL
When you say a "kit" what all came with it? I saw bar kits that included a muddler - they are part of the site that is in the last link. Click on "Gift Sets" on the left and you'll find several different sets that include one.