They are billet roller 1.6 (Erson) but after much measuring they actually are closer to 1.5, even including angularity loss. Major disappointment, bed was made so..... After lash I have .550”. The B3 kit compliments this but I have some HS (Mancini) rockers that I mocked up after the fact and they are 1.6 and yielded .602” before lash, would be .581” after, and they had good stem positioning and sweep pattern no correction. Those may be going on in the future