When ISUP first appeared in Chinese market in  2013, our factory joined this industry. ISUP is a purely hand-made product. During the passed 8 years, our technicians and workers have accumulated a wealth of experience. Our workers glue  the drop stitch top and bottom together with much fewer  bubbles.  which ensures the low air leaking rate at the first step. Though, to be 100% sure, we inflated every boards with 15PSI and left for 24 hours to test any possible air leakage before moving on to the next process. For those found to be leaking, we will apply soapy water one by one to detect the leaks and repair them at once. After the product is finished, we will have a professional inspector to check all the parts of the board before packing.