It is proprierary, but yet pretty cheap and it comes with a comprehensive datasheet without an NDA: <a href="http:&#x2F;&#x2F;pdglive.lbl.gov&#x2F;Particle.action?node=S003" rel="nofollow">http:&#x2F;&#x2F;pdglive.lbl.gov&#x2F;Particle.action?node=S003</a>