Practice and familiarize yourself with the P2P Prepared2Protect HDP 50 pistol by using these inert powder rounds compatible with the HDP 50 from T4E, a brand of Umarex. The powder is enclosed in a blue and white shell that is made to burst upon impact creating a cloud of powder. A great reactive product for confirmation of rounds on target. The hardness of the surface the powder ball impacts, as well as distance, will affect performance. Practice to engage up to 20 feet.