As it s name implies, this is the smallest of the three barrels, which is sometimes used instead of the spine corrector when there are flexibility issues with spine of the student. The barrel is smaller with a gentler radius on which to lay the spine, this makes it easier to keep correct positioning on the barrel when performing the exercises. This barrel is also used in conjunction with Classical mat work exercise order once again to promote opening of the hips, chest and shoulders while at the same time adding challenge to the power house and bringing variety to the mat work.