SUPER-COMP is an extremely rich medium that significantly increases the competency of the cells when using a simple RbCl/CaCl means of preparing competent host cells. After cells are made competent, they are immediately ready for DNA uptake. For maximum transformation efficiency, store for 12-24 hours at 4°C to increase competency 4-6 fold (at 48 hours they will be approximately as efficient as when first made). Competent cells can also be frozen in aliquots at -80°C after adding glycerol to 20%.