Sigma Summit is engineered to stretch up to 300 percent due to an easy unwind which makes it ideal for high speed, high pre stretch equipment. Sigma Summit is engineered to stretch up to 300 percent due to an easy unwind which makes it ideal for high speed, high pre stretch equipment. The uncompromising state of the art cling package promotes the adhesion of all film layers , while the no cling surface on the outside allows pallets to touch and remain intact when pulled apart. This saves space in trucks and warehouses.