The yellow and blue are the same except for the terminals and are both deep discharge tolerant. The red is described as withstanding 3 or 4 deep discharges and blue as taking 20 to 50 deep discharges. Notice the yellow/blue have less capacity than the red, yet the outside is the same size. This is because more space is allowed between the wraps of lead electrode. Deep discharges and recharges grow lead crystals which stick out from the plates and can cause shorting. More gap means more life, but less surface area.
Roy