Block Current America

Block: Term Securities lending facility

Web site http://investopedia.com/terms/t/tslf.asp
also I used http://www.newyorkfed.org/markets/top_terms.html this is the better web site.

This allows "primary delears"(from website listed above) to borrow money for 28 days from the treasury. The Securities lending Facility holds a weekly auction "*for basket of securities in $10 million increments." ( from website listed above.")

Meaning
*"for basket of securities in $10 milloin increments"- this means that the primary delears can bid on the right to borrow money from the treasury in amounts of $10 million.