The Comrades retractor (CMR-RET) sets are surgically invasive retractor devices designed to be used to assist wound retraction in the posterior lumbar region. There are 2 versions of the Comrades Retractor-Folded (F) and Straight(S). CMR-RET-F is advised for retractions in the range of 90 mm to 155 mm. CMR-RET-S is advised to be used for retractions in the range of 40 mm to 90 mm.