The idea behind TechT's MRT (Mass Reduction Technology) Bolt System is to reduce the moving mass inside the marker to the bare minimum. The MRT Bolt for the BT TM-7 & TM-15 marker is only 6.5 Grams. Lightening the bolt means that the marker will naturally have less kick/recoil and take less pressure and time to move the bolt back and forth. This means your marker will produce less vibration and recoil with each shot. This in turn allows you to stay on target better and hence shoot more of your opponents. Our testers also said they experienced better accuracy. and increased shots per tank over the stock bolt.