Where an you find Knuckles advances in sonic battle 2

well most of them they basically just but in front of you but there are two that will make the game easier
sunglasses- you can see invisible items- in the space level inside the lava pit thing wait till it opens then go on to the bottom platform and it there
something that's like an oxygen tank (forgot name)- you can swim with out timing out- in the mine once you drained all the water go to the bottom find a hole in the wall go in there should be some water dive in it swim in the small cave go up and its there (i forgot if you drain it to level 3 or 2) hope this helped