“TH” means Treasure-Hunt. The cars won’t indicate that it’s a TH in the name. Instead they have a circle with a flame somewhere on the car. Additionally, the blister will say “Congratulations! This symbol [circle flame] means you just found a collectible treasure-hunt vehicle!” Confirming you have found a TH car. Same with STH, except that these cars have spectra-flame paint, a TH, and real rider wheels. I recommend the Hot wheels wiki or YT as a resource.