Stem Trainer is the Most Powerful Low Stress Training Product On The Market. The Stem Trainer may be fixed to the stem or branch of a plant with rubber bands. The rubber bands allow for the natural movement and growth of a plant without constricting the plant’s stem or branch. Once in place, the splint may be arched systematically, without the fear of overbending and damaging the plant, to manipulate the stem or branch by arching it away from the center of the plant, exposing the underlying growth to the light from above. This allows for full penetration of the light’s rays, maximizing photosynthesis. This produces larger, healthier, higher yielding plants.