The standard pre-stretchers, which hold a 750 mm roll, are made of aluminum to avoid tack build-up from the film. Both outer ends of the aluminum rollers are cone-shaped to maintain the optimum width of the film and reduce the risk of tearing. The special ribbed profile of the aluminum rollers keeps air and water away from the film. The location of the pre-stretchers makes it very easy to change the film rolls. The standard pre-stretch of 70% is reached by a low-maintenance and low-noise gear transmission. An optional 60% pre-stretcher gear kit can be installed to change the standard pre-stretch to 60% to adapt to difficult wrapping conditions.