The video is about making a canon using PVC pipes. Take two seven inch cut PVC pipes and fix both of them into a PVC 'T'. Two PVC 90 degree corners should be taken and join them to previously taken 7" pipes. Note that the 'T' part should be at 45 degree angle. Then comes two 22 inch PVC pipes and has to be placed in the ninety degree corner section. Take PVC caps and drug a hole in the center. This place has to sealed well. Now take a three inch cut PVC pipe and fix in the 'T' part. The bolt has to be glued into the raised part and it's ready.