3D's have about the same pin size/height as PL Holeshots. 3D's have the reinforcing bars on the outside though.

They work well on a lot of different surfaces, including dusty outdoor as long as there is a hard-base. Indoor too if it's a newer layout with some dust on it. They work good on grooved and slick-groove surfaces. My local track is usually really hard, faintly dusty and varies from med to low-bit and even slick. They work pretty much all the time and are safer/easier to drive on that DD front/Barcode rear. And have a bit more linear steering feel than just barcodes all around.