For use with the Twister T2 Trimmer Twister T2 Rails enable quick and convenient angle adjustments. Changing the pitch allows for faster or slower pass-through rates, giving the operator greater flexibility for speed and output quality. Adjustment Range 3.9″ / 98.5mm (0 – 8 Degrees) If you want to use rails for Tandem (two T2 Trimmers) Purchase one set of single rails, and the extension rail.