Promega, L2011, HB101 Competent Cells

HB101 cells are rec A–, which minimizes recombination events, and contain a restriction-minus background ( hsd S20) that allows better representation when cloning methylated DNA. HB101 Competent Cells are suitable for vectors that do not require α-complementation for blue/white screening.
For researchers doing more than one transformation, competent cells are available in standard format (200µl aliquots). For added convenience, single-use competent cells (50µl aliquots) also are offered.
HB101 Competent Cells are prepared according to a modified procedure of Hanahan.
HB101 Genotype: F–, thi -1, hsd S20 (r B – , m B – ), sup E44, rec A13, ara -14, leu B6, pro A2, lac Y1, gal K2, rps L20 (str r ), xyl -5, mtl -1.
Reference
Hanahan, D. (1985) DNA Cloning , Vol. 1, Glover, D., ed., IRL Press, Ltd., 109.