I found a mysterious black object in my drivers seat console with the title: B&M shift plus, with a switch on the top. it has a cord leading to who knows where. I obviously bought my car used. What does It do? And is it okay for it to have it?

i was looking at shift kits for my automatic transmission in my ws6, transgo actually makes a shift kit for it,what do you guy's think about putting in a shift kit? has anyone on here done it to there's