Traction devices aim to increase the length of the penis by stretching the Penis tissue. A person places a weight or small extending frame on the flaccid penis to gently lengthen it. According to a scientific review from 2010, penile extenders are the only evidence-based technique for lengthening, and the results may not be inferior to penile surgery. Several studies have investigated the effects of traction devices, with varying results. Some results suggest that the devices can lengthen the penis by as much as 1–3 centimeters (cm).