Pro Boom is manufactured to optimum specifications. Steel rings rather than rope on the ends facilitate connecting the o-ring to the bit snap. Both inner sock and outer net pulled through the o-ring give the maximum tensile strength possible. O-rings and bit snaps are fastened with clips to keep them from rotating through the rope and net. The tear drop bit snap is easier to connect than rounded corner rectangular bit snap. Polyester netting rather than polypropylene netting gives inherent UV protection and more elasticity to hold its shape. Pro Boom is filled to the maximum resulting in no voids along the length of the boom. 4 booms per case. Sold by the case.