The top and second rings are diamond lapped Total Seal parts, with a thickness of .0415-inch. It's a traditional "gapped" ring, and Nelson will run minimal gaps in the neighborhood of .014-inch for the top ring and .018-inch for the second ring. After using just about every ring out there, we feel its noteworthy Tom decided to go with a top quality traditional ring design, and those considering more radical or less durable rings for their own engines should take note. The diamond lapped rings are precision crafted to seal perfectly to both the cylinder wall and the piston groove, and they are thick enough to offer excellent durability. For those questioning the ring choices of past Engine Masters Challenge engines as not being truly streetable, here's a move in the right direction.