The studies that I have seen and the traction study summarized on altpenis.com claim that these traction devices increase both length and girth. I believe most of us on this site use multiple PE methods and devices though so it might be difficult for some of those who have achieved girth gains to determine whether they have come from jelqing, ULIs and horse squeezes or using this device.
The studies that I have seen also claim that the test subjects wore these devices 8 - 12 hours a day. I did the math and averaged the figures quoted in several studies. I determined that if I used one of these devices exclusively that I would have to wear it between 1000 and 1500 hours in order to gain an inch in length. Some of the studies also seem to imply that since traction induces cellular growth that there is virtually no limit to the gains you can achieve.
Here is a link to a summary of one of those studies:
http://www.altp enis.com/penis_ … _research.shtml
This study claims that the research subjects gained an average of .47 centimeters (.1888 inches ) per month in Erect length and .48 centimeters in flaccid length. They also claimed that the monthly girth increase was .80cm - ( this seems very unrealistic to me after studying the PE data on this site). In addition, after using the device for six months the subjects gained 27.5% of their initial erect lengths.
Alas, I am a skeptic. Note I said skeptic and not cynic. I still bought one! It would be interesting to take a test group of volunteers from this site who were willing to wear these devices 7 days a week for 8 hours a day and report their results back to us. It would also be interesting to have two test groups, one just beginning PE with this device and one group who had been PEing long enough for growth to begin to slow notably then compare the results between the groups.
If I extrapolate from this particular "study", with a starting length of 7.5 inches I could expect to be 9.56 BPEL if I used the average percent gained over 6 months or 8.832 if I used the average length gain achieved during the test period. If I thought that were true I believe I would take a six month sabbatical!
In most of the "studies" and advertising claims though the key ingredient tends to be time. More hours = more size.
(365.25/2) = 182.625 Days in 6 months
(182.625 * 8) = 1460.8 Hours spent in traction
3.33cm/1.332 Inches Average Reported Gains for 6 month, 8 hour, 7 day per week use of device
( 1460.8/1.332 ) = 1096.697. That is approximately 1100 hours for an inch. So, according to this study, if I used a traction device exclusively 6 days a week, 4 hours a day, I might gain an inch in 46 weeks.