PenFed typically keeps the CD rates unchanged for a month. They used to list the end date at the bottom of the rate table, but they ended this after their last 6% CD special last fall. That was the first time that I can remember PenFed ending the CD rates before the end of the month. After that, they stopped including an end date in the table.
For more details about PenFed's CDs and joining PenFed, please refer to this PenFed review post. PenFed makes it easy for anyone to join and open accounts online.
In addition to high CD rates, PenFed has several other competitive banking products including a cash back credit card with 5% cash back for gas purchases and auto loans with very low rates (see post).
PenFed is one of the largest credit unions in the US with $10.5 billion in assets and 769,231 members. It's federally insured by the NCUA (Charter # 227).