There are quite a few more than two. The red is high temp semi permanent that requires heat and or special tools for removal. The blue is the next grade lower. Green is low strength and can be applied in advance and the fastener installed after it is dry. Yellow is a type of formula that wicks into the threads and is very low strength. These are the most common consumer Loctight products. All in all there are 17 different Loctight retaining products designed for the automotive industry alone. The last I heard from Henkel (owner of Loctight) there were 237 formulas of retaining compounds.
Just a warning from someone who uses and deals with the product everyday. Just a dab will do. I have seen the blue used to excess and end up ripping the threads right out of steel parts.
Pete